Hot Rod Forum banner
Status
Not open for further replies.

crate chevy 302?

61K views 106 replies 77 participants last post by  fleenorracin 
#1 ·
is there a company out there that sells any long block or complete chevy 302 crate motors? i've done some half arsed looking but have come up empty. i want to stay away with used 302's cause they're going to be pushing it with regards to age and wear. your help would be greatly appreicated, thanks.
 
#3 ·
1967 302 Chevy's used a 327 block and a 283 crank (3.0 inch stroke X 4.0 inch bore small journal crank).

1968-69 302 Chevy's used a 350 block and a 283 crank (3.0 inch stroke X 4.0 inch bore, big journal crank).

All had 5.7 inch rods I beleive.

All these engines were produced for homologation in the Trans-am series to compete against the 302 Ford Boss engines that dominated at the time.

All 283 cranks are forged so you can use any one to create your engine, just make sure you get the right size journal block to suit. You can get spacers to fit a small journal crank into a big journal block or have the crank ground to fit, I don't recommend either. Why you would want to destroke a perfectly good 350 or 327 is beyond me? Are you trying to get into a specific class of racing?

They don't sell 302 crate motors because everyone wants the bigger cubes. Here's a site with a good breakdown of Chevy engines.

<a href="http://www.v8s-series.freeservers.com/sbc.htm" target="_blank">http://www.v8s-series.freeservers.com/sbc.htm</a>
 
#5 ·
it's like 4 jaw says, this size engine was made for trans am racing,i believe cubes had to be under 310 cubes. you had to be there i guess, they were screamers. made 67 to 69, factory balanced, blueprinted, some dynoed at 375 horse. i was 17 in 69, hard core race fan, i dreamed of a 302 in my 57 chev.
 
#7 ·
thanks for the feedback. it might be interesting to build one up with some good power numbers, race it then tell the looser in was a 302!!! just my goofy dream i guess. for all of those who didn't know they chevy made a 302 well they did and they revved hard. come on i'm 18 and i new that. all smiles!
 
#8 ·
69 Z-28, 302, 4spd., my dream car. 4jaw, ford made its 302 after chevy, I beleive 69 or so. Any combination of 3" stroke and 4" bore will make a 302. But I think originals had large diameter mains, nitrited crank, 4 bolt blocl, 2.02" intake valves, 1.6" exhaust valves, aluminum dual plane intake, and Holley 750 cfm carb. If you build this get a car with weight over the rear tires, put in some low gears, a 5 or 6spd trans, and have some fun. If it hooks up at all you will break parts. I drag raced with small engines for years. There is not much that can compare to leaving the starting line at 11,000rpm, and then rowing through 4 gears (clutch assisted)in 10 secounds. Yep I am old, but I still remember.
 
#11 ·
Hey everybody, Chevy did make a 302 and from what I've heard it was the motor sought after back 67-69 camaro's, ford makes a 302 also, not a prayer
against chevy's 302,a rare factory motor. If you can get a hold on a used factory chevy 302, I'd do it in a heart beat.Watch your casting dates
67-69 only I believe.Or watch for a Tonawanda
built chevy motor,327-350's. Tonawanda built some
pretty strong power plants
 
#12 ·
One thing I always try to do is leave room for error when posting 'cause there's a lot of room for error in the world of cars. Halloweenking at least said "to the best of my knowledge" allowing room for error. But Ford definately did not make it's 302 after Chevy, it had nothing to do with Chevy. In 67 Ford decided to bump the 289W to 302 cubic inches for the 68 model year. I think in 68 Ford used the 302 and 289 version, but that's not important. I personally just think it's a good idea to try and not give specifics unless you're sure.

[ April 12, 2002: Message edited by: dmorris1200 ]</p>
 
#13 ·
Your are all correct, the Chevy was produced first and it was Ford who decided to jump into Trans-am racing by building the 302 Boss. Sorry I got my "facts" all backwards, hey I'm not perfect!

One of my favourite sounds is a short stroke small block with low gears going through the gears and hitting 8 grand at every shift.
 
#14 ·
I was alive and well when both the Boss 302 Ford Mustang and the 302 Chevy Z-28 Camaro came on the scene brand new. It would really be hard to say which was the best or the baddest, they both would run like a scalded dawg..right off the show room. I have been a party to a '68 Z-28 many nights in my teen age years, which belonged to my best friend, but got my butt kicked driving a '68 383 Charger by a '69 Boss 302....not just a little either...I mean KICKED. The Ford and Chevy were both bad boys in their day. PACO
 
#15 ·
I was alive and well when both the Boss 302 Ford Mustang and the 302 Chevy Z-28 Camaro came on the scene brand new. It would really be hard to say which was the best or the baddest, they both would run like a scalded dawg..right off the show room. I have been a party to a '68 Z-28 many nights in my teen age years, which belonged to my best friend, but got my butt kicked driving a '68 383 Charger by a '69 Boss 302....not just a little either...I mean KICKED. The Ford and Chevy were both bad boys in their day. PACO
 
#16 ·
I would say today that all 67-69 z28 Camaros are rare. I was 18 in 67 when they came out and although I've never been a Chevy fan I can tell you that they ran hard. What the younger ones don't know is it was an engine that gearheads had been building for quite sometime. we knew it as a 301 on the street. 67s are the rarest z28 there was only around 700 built that first year,I remember only one 67 that a guy had that worked for a Chevy dealership,he had also added dealer installed cross ram dual quads and dealer installed headers. If memory serves me correct the factory would ship these parts with the car in the trunk and the dealer would install them. Again if memory is correct they used a cowl induction set up with the dual quads. In 68 nothing really changed other than alot more people knew what a z28 was and bought them. 69 was the last of the first generation Camaro and the 302 also. There were a few other changes made in 69 though,real early 69s had a chamberd exhaust system,there was no mufflers on the car,the exhaust pipes were supposed to quiet it down,I thought they worked great but they were to loud and they did some sort of recall and replaced them with a standard system, also in 69 they added an air pump,the begining of smog control,that would disappear as soon as someone would buy the car.Most all of the 302 z28s had 3.91 gears or steeper,I think the 3.91s were standard,they all had posi-traction, 4speeds with a hurst shifter,202 heads,alum intake,holley carb,solid lifter cams,chrome valve covers,and air cleaner.They were mostly plain jane cameros with one purpose, to run hard and that they did very well.Back then when Ford came out with the Boss302 they cleaned up on the road courses the cars were built for, but on the street or the real world for me,the z28 was quicker. Thanks for letting me ramble on and remember a very fun time from along time ago. :D :D :D
 
#17 ·
302 crate motor that my dad picked up in the 70's just sits the garage. He said when it acctually reved 10k rpm was easy to hit. I know is a crate motor but did it have the same HP as the stock motor from the Camaros? And does anyone know what teh real horsepower was from just a stock Z/28 302? With no modifications, just stock. Also if anyone has a cross ram for the motor, i am interested cause we found a car to put the motor in, and he always wanted a crossram for it.
 
#18 ·
Was reading the posts on the crate 302, thiught I would add my 2 cents. I am the owner of a 302. Mine came with my 69 Nova, go figure. Mine is a March 68 block with a large journal original steel crank. The casting is 3279. Unfortunately or fortunately the 302 did not have a specific block made only gor the 302 there were several blocks used to create the 302.
The mis conception is that all 302's were small jrnl motors, this isnt tru. Even the local speed shop insisted mine was a small journal, until I proved it. The heads on my motor even have the correct casting number used on 68/69 302, but mine oare replacement cast iron units from another local speed shop, even has there name stamped in the ends. 302 were created specifically for the Trans Am circuit. The are extremely high reving motors, thats why one would desire 2 short stroke motor, less heat..... etc..
There are several advantages to min motor. If I explode the crank, 383 stroker kit would do just fine. Maybe some relief cuts in the cylinders to clear the rods, we're set.

Thanks for reading, Have a nice day !!!

See my hotrod at:
<a href="http://www.godsrods.com/features/tomelam.html" target="_blank">Gods Rods</a>
 
#19 ·
Hi, rodders,
I just had to post here on the 302 stuff. Maybe stir up some debates...Back in 68 (day of the z-28) my buddy and I bought a crate long block right from GM (before crate motors were known).I think it was called a 'replacement motor'. we put in a roller cam and rockers and valve springs, added Enderle injectors, Vertex mag, and a flat dragster oil pan and put it in our Junior fuel dragster. Direct drive in those days with a slipper clutch. We ran 98% nitro (the can as it was called) and ran low 8's and high 7's 1/4 mile at 195mph plus. Car weighed less than 1100 pounds. (none of the saftey stuff we have now..like aluminum bellhousing etc.) We didn't have 'tars' like today so we smoked either the clutch or the 'tars', or both.. If you are young?? enough to rember Gene Adams and some of the other Junior fuel guys you will rember this class. It was fun and relatively cheap. the motors didn't last too long but at $400 bucks you couln't go wrong. a lot of guys bought these and ran them right out of the box and ran tough in other classes. Usually just a good roller cam and rockers plus ignition and carbs or FI was all that was necessary for a killer motor that would rev way past 8 grand.
guys that are used to todays torque monsters have to know that we ran 4.11 and 4.56 gears on the street and didn't give a d...m about gas mileage of 4-5 mpg since gas was .25 to .35 cents a gal for premium 99 octane or better.
Yeah the z-28 was pretty fast with 4.11 or 4.56 gears and 2.2 low gear t-10. but...let me tell you a lot of these got new a.. h..les torn when they ran up against 66-69 chevelles with 396 and 66-69 gto with 389 tri-power 2.54 low gear and 4.1 to 4.56 gears. a road runner with 4.56 and 4 spd was pretty formatable too. forget the hemi on the street you just waited him out..sooner or later he needed new plugs or carb adjustment. gotta remeber we didn't have the 'tars' of today so we didn't race from a stop often. 20 mph rolling start was pretty tough for the z-28 to compete against cu in. The chevelle really wasn't much heavier than the z-28 was and was pretty sure footed for its day. a Z-28 caught with the revs down was sirloin steak for a chevelle. I have to admit that hearing a z-28 wind out on the street back then was pretty impressive..especially with the headers uncapped. I'm sure to ruffle a few feathers but I worked on these in a hotrod shop for a long time as well as most of the other factory hot rods. A road test was part of the work order. the Boss 302 Ford was pretty impressive too. it would rev to no end and was tough too. In the road races and parking lot races it was tough to beat. The Boss 429 was the same, rev the h... out of it and go fast... then come and pay me a lot of cash to fix it..Some of the truly wild stuff was never meant to be on the street especially the Fords. Most were techinically not able to be licensed from the factory. Easy to get around however. go to the junk yard and peal off a vin tag and say you lost the title. Some times the junk yard would sell a title for ten bucks too. the post above about how many of these wild cars actually made is true. I had a 57 chev 210 2dr for which I bought a 283 hp FI engine from a wrecked stock car plus the title tag, then bought a 4sp from another wreck and viola!!! I had an original 57 chev sedan 283 hp FI 4sp. Totally legal for racing!! supposedly only 50 or so were actually made by the factory for NASCAR. D...m fast car right out of the box. Ran 106 mph 1/4 mi with my own fender well headers and modified ignition.
Lots of us ol' timers can fill you 'young whipper snappers' in on the early days of hot rodding when it was fun. Most of us could write a book about the wild things we did that would put you in the slammer for a long time today!! The worst ticket I got was extreme loud ex,no front bumper, causing extreme disturbance, and...'exhibitionistic' driving. Just for doing a smokie burn out in the mall parking lot. cost me 200 bucks for a lawyer to get me off with a promise to never do this again and to never drive my hot rod on the street again. "thank you your honor sir, no your honor sir I'll never do this again your honor, I'm totally sorry..sir your honor , I didn't know what I was doing honor sir, I'll put the car away, and go back to school, your honor". You should have seen the smokie I did the following weekend!!!
bentwings
 
#20 ·
I am new to the board, but thought I'd post on this. I have a home-brew 302 that might interest you. First some history. Chevy was first to debut a 302 in '67. Ford debuted their's in '68. The Chevy 302 of '67 was built off a standard 327 4" bore small journal (the only size in '67) 2 bolt block. In '68 Chevy used the new medium journal 327/350 4 bolt main block to build the 302 with a new forged 3" stroke crank. The '67 crank was a slightly modified 283 forged crank. As far as I know the only difference between a 283 and 302 application was the rear counterweight(flywheel flange) It was perfectly round on a 283 and had a small notch cut in it for the 302 balance. All engines used the standard rod length of 5.7 inches. Rods of course matching the respective journal of the crank. I do belive some small journal "MO" engines were installed in '68 Z's. The large journal engine being a "DZ". Ok..on to the home brew. I used a standard 327/350 4 bolt 4" bore block with an honest DZ 302 crank that I was lucky to keep standard. Instead of the heavy TRW forged 302 piston I used a much lighter SRP piston with a compression height of 1.560" (standard 350). How might that fit you may be asking? I used the new powdered metal GM rods the measure 5.94" We put in some ARP bolts, resized them and off I went. Edelbrock Victor Jr. heads and a PRP "Bowtie" clone intake finished it off. I have installed 3 cams in this combination, searching for a good compromise. First I used the second-design solid flat tappet (262/273 .512 .536 112)and that thing wouldn't idle below 1400 RPM. I mean 1300 and it shut off. It was way too...just wrong. I decided to step up to a solid roller next. 236/242 .564 .570 on 108. This cam ran like a s.o.b. until I broke a used lifter I had. 8000 rpm no problem with titanium retainers and good springs. Instead of regrinding the same 'ole cam I had a slightly smaller one done that is 230/236 .552 .564 on 108. With the excellent flow of the heads this one still goes 7800 rpm and has better low end response. The engine is 11 to 1 and I run 39 degrees timing with Amoco Gold gas. Its in my '69 Camaro and I have a 4.56 twelve bolt and a SuperT10 transmission. No matter what anyone tells you, you just can't expect a synchronized transmission to shift at 8000 rpm. Clutch shifting at 10,000 rpm isn't going to happen. No matter what the 'ole timers say. The 302 isn't going to live up there either with stainless valves and stock rods. The pistons are way too heavy for that. But sane 7500 rpm shifts are possible with pretty good reliability. I bought an Offenhauser crossram and the correct Holley carburetors to install on the 302. The manifold overhangs short valve covers so my tall GM aluminum covers and stud girdles won't fit. Maybe sheet metal Moroso covers will. I built the engine with the intent of running the crossram. Hope some of this was useful.

[ September 23, 2002: Message edited by: rhsmark ]</p>
 
#21 ·
Originally posted by Biggarmike:
[QB]There is a lot of good info here on the 67-9 302. It's pretty funny now, everybody is cloning Z-28 Camaros. the original 302 wore DZ as engine code, good luck finding one. <hr></blockquote>

The original 302 Z28 engine code was MO. Check your books. DZ is 69.

I had a 67 Z28 in 68. One of 602. There were good but non as good as people WANT to believe. 67 Z's were unmarked. No emblems. I rode in mine when it still had the paper tag on it, Then bought it when my buddy went to Vietnam. He never came home....

Most everywhere in this land, Big Block Camaros and Chevelles ruled the roost. You can not take a 302 Chevrolet factory rated at 290HP and out run a 396 - 375HP Camaro or Chevelle with any kind of regularly. Like almost never. If Both cars are tuned equally and driven by comparable drivers......... by by 302. My 67 was stolen in 69 and I replaced it with a Forest Green 69 Z28 RS. After the 90 day warranty ran out, I took the 302 out and put in a L88 427 crate engine. Then I could run with the Big Guys. Takes a big block to beat a Big Block.

I do argee that MOST Z28's you see today at local shows, cruise nights and on the street are fakes. Clones is a polite way of saying FAKE.

The Z28's that show up at the National judged shows are mostly real, over restored but real.
 
#22 ·
The chevy 302 was made in 1967 with a 327 and a 282 small Journal crank. It had a 3.000 inch stroke witch is the shortest stroke chevy ever put into a small block.It was made for the tran-am raceing. It was made in 1968 and 69 as well but it had a 350 block and a large journal crank. This motor was a great reving very powerful small Block and I think it might have been the most powerful small block stock that chevy ever made. I just bot one and I think it's the bome I can't weight to run it on the 1/4 mile in the spring.
 
#23 ·
I was in high school in 67 when a friend of mine got a new 302 camaro.It was called rally sport 302 and this was before we ever heard of a Z28!Yes it definitly was a 302 I remember it well.Had a lot of fun with that car.Anyone know anything about a rally sport 302?
 
#24 ·
Some more info on the Chevy 302!
In 1967, Chevrolet introduced the Z/28 option package which included among other things, a special 302 cubic inch small block. The engine size was a result of the SCCA's 305 cubic inch displacement limit in the Trans-Am series at the time. The 302 turned out to be one of Chevrolet's finest small block offerings, and the engine stood in stark contrast to the ever increasing size of the big blocks used in the muscle cars of the day.
To arrive at the SCCA legal 302 cubic inches, Chevrolet used a 4.00" bore and a 3.00" stroke resulting in a very oversquare (the bore is larger than the stroke) combination. In overly simple terms and ignoring such important design factors such as bore / stroke ratio, an engine with a short stroke has the ability to rev higher due to slower piston speeds. As an example, think of two engines, A and R. Engine A has a stroke of 3.00", while engine B has a stroke of 4.00". If both engines are turning at a speed of 4000 rpm, the pistons of engine A have less distance to travel than those of engine B. Since both engines are turning at the same rpm, the pistons of engine R have to cover more distance in the same amount of time as the pistons of engine A, resulting in higher piston speeds. Short stroke engines, therefore, can run higher rpm with greater reliability and less stress on the reciprocating assembly. This is the approach Chevrolet took when designing the 302 for SCCA competition.
The blocks used in 1967 were casting number 3892657. These small journal blocks were also used for 327 and 350 cubic inch engines as well (all three engines used a 4.00" bore). 1968 models used block casting number 3914678 and featured the new style large journals. The 1968 block was also used for the 327/210 hp and 350 295 hp SS engines. The blocks used in 1969 featured thicker webbing around the mains and used nodular iron 4 bolt caps. A common misconception is that 1967 and 1968 302's were 4 bolt blocks, while actually the only engine to use 4 bolt main caps was the 1969 version.
The crankshafts used were forged steel, tufftrided pieces in all three years. 1967 models used a small journal crank with 2.000" rod journals and 2.299" main journals. 1968 and 1969 models used a large journal crank featuring 2.100" rod journals and 2.449" main journals. The forged cranks were deemed necessary due to the high rpm the 302s were expected to see.
The connecting rods varied considerably from year to year. 1967 models used what was the standard small journal rod of the time with a pressed in wrist pin and 5/16" rod bolts. Two styles of rods were used in 1968, the first being a strong large journal rod using a pressed pin and larger 3/8" rod bolts. Middle production 1968 rods were changed to a floating wrist pin design.
Both early and late style 1968 rods were shot peened (a stress relieving process) at the factory. 1969 engines continued to use the late 1968 style floating wrist pin rod.
All 302s used a special baffled oil pan (the baffles prevented the uncovering of the oil pump pickup as a result of the g-forces generated during acceleration, braking and cornering) and a high pressure oil pump.
All 1967 and early production 1968 302s used a pressed pin design forged aluminum piston with an 11.0: 1 compression ratio. Late 1968 production pistons switched to a floating pin design. The 1967 and early 1968 pistons used a dome design taken from the 327/350 hp engine, and featured two individual valve reliefs in the dome. Late 1968 piston design has a long notch-type valve relief cut across the entire dome. 1969 models featured a new 11.0:1 compression impact extruded piston with slipper skirts and a floating wrist pin. The dome design was the same as the late 1968 pistons.
Cylinder heads used on the 302s can be a bit confusing. In 1967, two different cylinder head castings were used on the 302, 3917291 and 3890462. Both heads used 2.02" intake and 1.60" exhaust valves. The confusion arises from the fact that the 3890462 casting was also produced using smaller 1.94" intake and 1.50" exhaust valves, although this head was never used on the 302. 1968 heads were also produced using casting number 3917291, but 1968 heads included a provision for a water temperature sensor not included on 1967 heads. Valve sizes were again 2.02" and 1.60" intake and exhaust respectively. To further complicate matters a small valve version of the 3917291 head using 1.94" and 1.50" intakes and exhausts was used on the SS 350 engines in 1968. So far that's two different versions of the 3890462 cylinder head and three versions of the 3917291 cylinder head! Both castings had the familiar "double hump" machined pad located on each end of the head. 1969 engines used head casting number 3927186 and featured the large 2.02" intake and 1.60" exhaust valves of the earlier heads. 1969 heads also have holes drilled and tapped in the ends due to a change in the alternator mounting method. All of the 302 cylinder heads, regardless of casting number, had the same characteristics. Large port volumes and large valves were used to facilitate breathing at high rpm, at the expense of low to midrange efficiency.
Fortunately, identifying the camshafts used in the 302s is much more straightforward than the identifying the cylinder heads. All three year model 302s used the famed solid lifter "30/30" camshaft, so named because of the .030" intake and .030" exhaust valve lash adjustments. This camshaft was also used in the 1964 and 1965 special high performance and fuel injected 327's installed in the Corvette. Again, due to the high rpm nature of the 302, a solid lifter camshaft was chosen. Solid (or mechanical) lifters require maintenance more often than hydraulic lifters, but are more reliable at high engine speeds than the hydraulic lifters. Hydraulic lifters tend to "pump-up" at higher rpm, which leads to valve float. This is not as much of a problem today due to the advances in valvetrain design, but was quite a concern in the mid-'60s. Specifications for the cam are .452" intake and .455" exhaust lift, 229 degrees intake duration and 237 degrees exhaust duration (both measured at .050" tappet lift) and 78 degrees of overlap (at 0 lift).
Chevrolet needed an appropriate intake manifold to take advantage of the other high performance engine pieces, and they settled on a single four barrel aluminum high rise design. The basic design of the manifold remained unchanged from 1967 to 1969 although two different casting numbers were used. 1967 and 1968 engines used casting number 3917610, and the intake featured the thermostat hole located off-center toward the drivers side of the car. The engine temperature sensor on 1967 models was located in a drilled and tapped hole next to the thermostat opening. On 1968 intakes, this hole is plugged due to the relocation of the sensor to the head. 1969 intakes, casting number 3932472, centered the thermostat hole and are otherwise unchanged from the earlier intake. As an over the counter option in 1969 (available through the parts department, never installed by the factory), the Z/28 buyer could order a dual four barrel aluminum cross ram intake manifold (casting number 3940077). This intake was designed so that longer intake runners and two carburetors could be used while fitting under the stock hood. In 1969, the intake came with a special ZL2 cowl induction hood and air cleaner. This intake performed poorly on the street, but when used on high rpm competition engines (the engine was designed for SCCA racing, after all) really came into it's element.
Holley 800 cfm dual-feed carburetors were used on all 302s, although list numbers differed somewhat on 1967 models. Cars built at the Norwood, Ohio assembly plant used list number 3910 carburetors only, while cars built at the Los Angeles plant used list number 3910 and list number 3911, the latter being used on cars equipped with an AIR (Air Injection Reactor) emissions system. California laws mandated that any new car sold within the state must be equipped with an emissions control system, thus the difference in carburetors.
All 1968 and 1969 302's used an AIR system thereby allowing the use of the same carburetor (list number 4053) regardless of assembly plant or car destination. The use of Holley carburetors on the 302's followed a Chevrolet tradition of using Holleys on their high performance engines. In fact, the 4053 carburetor also saw duty on the 396/375 hp big blocks of 1968. Holleys are still used on the vast majority of carbureted competition engines and offer a high degree of adjustability, performance and reliability.
The exhaust manifolds used on 302s in 1967 and 1968 were little more than the standard "log" type found on most small block equipped passenger cars. The only major difference between years is non-AIR equipped 1967 versions have no provisions for smog tubes. Chevy must have felt that the majority of Z/28 owners would bolt on their own headers if so desired. In 1969, Chevrolet made available a tube header option for the 302 engine (when this option was ordered, the engine in the car came equipped with exhaust manifolds while the headers were shipped in the trunk of the car) along with a low restriction chambered exhaust system. The chambered exhaust was discontinued in May of 1969 due to problems with passing noise laws.
All 302s used a standard single point type distributor, although the advance curves were optimized for the needs of the 302.
What all of these various pieces added up to was a healthy small block rated very conservatively at 290 horsepower at 5800 rpm and 290 ft. lbs. of torque at 4200 rpm. Rumor has it, however, that the same engine produced 350 horsepower at 7000 rpm on the dynamometer! Why would Chevy underrate the engine? Certainly insurance reasons come to mind, along with the desire to understate what the engine was capable of lest the various racing sanctioning bodies penalize the teams that chose to run the Z/28 in competition.
Road tests of the day praised the engine that Chevy put together. While most testers found the lack of "bottom end" power a nuisance, the 302 more than made up for that shortcoming with a very strong top end rush. One tester likened the pull of the Z/28 in the upper rpm range as being similar to a 426 Hemi! That's high praise indeed for an engine with two-thirds the displacement. Quarter mile times were in the low to mid 14-second bracket, depending upon the conditions the test was performed under. Modified 302s used in Trans-Am racing generated in the neighborhood of 450 horsepower, which is an amazing amount of power from 302 cubic inches with enough reliability to win SCCA championships in 1968 and 1969.
The 302 powered Z/28 was very successful in both NHRA drag racing and SCCA Trans-Am racing from 1967 to 1969. The Penske team with Mark Donahue dominated the Trans-Am series in 1968 and 1969 (winning manufacturer's championships for Chevrolet), while in 1968 Dave Strickler won the IHRA Super Stock world title in a 302 powered Z/28. That the engine and thus the car was so successful so soon after its release is a testament to the effort that went into the project by Chevy's engineers. It is, without a doubt, one of the all-time great small blocks produced by Chevrolet.
My vote?? The 302!!!!!!
<img src="graemlins/drool.gif" border="0" alt="[drool]" />
 
#25 ·
RHSMARK has done it with his buildup.
The 302 is now an easier build with standard parts.
The nice thing about the 302 is a large bore, short stroke.
This allows higher revs, hp, and fuel economy if the right cam is installed.
GM used the 5.7 rods for everything and made up the diffence in stroke by changing the wrist pin height.
To build a 302 you would need a 4" bore piston with a 1.785 pin height.
The 302 is the only engine that has this geometry.

Along came the LT1.
The LT1 lower end is just like the 350.
GM decided to make a 265 (4.3L) V-8 with the reverse cooled heads for the Caprice and Roadmasters.
One option was to start making the 3.75 bore pistons with the 1.785 pin height due to the 3" stroke.
Another option was to increase the rods to 5.94" and use the 305 pistons with a pin height of 1.545"
GM made longer rods so the "L99" has a 3" crank and 305 pistons.

With these parts available, a 302 can easily be made with factory components.
The LT1 engines were reversed cooled. (water flows thru the heads, bypasses the intakefold, then the block).
This allow higher compression ratios with 87 octane gas.
A 302 can be built using LT1 350 pistons, and L99 rods and crank.
This will drop the compression ratio from 10.5 to about 9.
Since the L99 came out in '94, it has large journals and a one piece rear main seal.
If lightweight 350 pistons are used, (same weight as the 305's), the crank should be pretty close to balanced.
Light pistons help in the high rev's and thats what the 302 is all about.
This setup is better that the earlier 302's since it is has longer rods giving a r/s ratio of 1.98.
I wouldn't use an LT1 block because of the computer junk and distributor.
L99 cranks can be had for $200 and a set of rods for $250.
There are votech heads out there designed for a displace of 305 that would fit just fine.

Vancouver, you can build a sweet 302 from basic to radical with mostly 350 parts, let us know how it goes.

I just want to clear up that rambling.
any 350 block (10105123)
L99 5.94" rods (12495072)
L99 3" crank (10243911)
any 350 pistons
any sbc heads

[ January 30, 2003: Message edited by: CNG_LT1 ]</p>
 
#26 ·
Ok Fellow Hotrodders, the 302 actually goes back to at least 1958 and they were built by those that were ahead of the most of us..Fellow Hotrodders. They took 57 283 blocks, bored them out to 4 inches, used 352 Ford pistons and I can not remember the specific rod. Anyway, it was a screaming 302 and it took GM and Ford another 8-9 years to realize the Hotrodders were pretty good engine developers. Sounds a little like 350 block + 400 crank uhh, stroker 383!! Hummm, now GM Performance (and others) offer the 383 as a new crate motor.

Trees
 
#27 ·
I like to reading the old HotRod books I remanber reading some thing about the 57 283s, I gase you could say a new twist on a old idea.When my dad was out looking at new cars in 67 I dont' know if it was a Z/28 or not but it was as plan as it gets dog dish hub caps the only crome on it was the bumbers it was a small black with a big tub air clener and two air tubes runing to the front of the car and it had a 4 speed trans it might look like some thing grand maw would have drove but by the looks of the motor Idont think so!! <img src="graemlins/mwink.gif" border="0" alt="[mwink]" />
 
Status
Not open for further replies.
You have insufficient privileges to reply here.
Top