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Help with Vortec Heads...please!!

10K views 25 replies 10 participants last post by  ThirdDegree 
#1 · (Edited)
305 Vortec heads.

Does anyone know how much they flow? How alike they are to their 350 counter parts? I have found very few reviews. Mostly bad.
 
#2 ·
Heads are supposed to be good

They are great for up to 400 hp but have limits. there really efficiant and make lots of power with low lifts and work flow best with flat or dished pistons in stock form..comp make a tool to machine the valve seat to fit regular springs and presto a good street head. most real high power stuff ive seen has been with roller tappet setups in the 270 @50 duration rangs lift doesnt need to be high to make power.
 
#4 ·
ThirdDegree said:
Does anyone know how much they flow? How alike they are to their 350 counter parts? I have found very few reviews. Mostly bad.
Where have you been? The magazines and books are full of Vortec reviews though we're 15 years past their introduction so they don't capture headlines like they used to.

In test after test compared to other production Chevy heads they deliver a 20 to 60 horse improvement by just bolting them on. 20 horses against older small chamber heads like the 462 or L98 when ported and 40 horses against these heads unported. 40 horses against large chamber heads like the 441 or 882 ported and a solid 60 against these heads unported. Plus the Vortec doesn't give up much bottom end torque, not enough to be felt. There are heads like the GMPP Fastburn which is essentially an LT4 head made for conventional coolant flow which will out flow the Vortec and certainly many aftermarket heads that will but they all give up a lot of bottom end to do it and cost a lot more. Then again the GM Vortec does require a Vortec specific intake and whether you get one from GM or off the aftermarket they are a bit pricey.

With Vortec heads and a cam like the Comp 262 to 268 with a 650 to 750 Holley and full length headers, the engine will make around 400 horses with an otherwise production bottom end. With changes to the piston to a D dish to improve the squish/quench characteristics and get the compression up around 9.25:1; it is possible to move that number toward 425 from 350 inches and have a very streetable motor that will take an automatic without having to up the converter stall.

Bogie
 
#7 ·
ThirdDegree said:
Im talking 305 vortecs vs 350 vortecs, not pre vortec vs vortec, fastburn etc. I have been doing Fords, like what it says in my intro post. The 305 is flat tappet. :(
305 heads while called Vortecs are not in that they do not include any of the features of the L31 Vortec found on the 350. The 305 vortec is simply a rehash of the 305 heads, some are slightly better than others but none offer the advantages of the L31 Vortec. Something GM's advertising department knows nothing about.

Back in the 1970s and 80s it was popular to use the 305 head as an inexpensive and quick way to get the compression up on a 350. For a 350 this took porting to 350 port dimensions and installing 350 size valves, an activity as like to find coolant as result in usable ports. Regardless of the ports achieved, unfortunately the 305 combustion chamber is inefficient at best. It has the spark plug in a distant location from the center of the cylinder bore as with the large smog chamber 350 heads of that era resulting in a long burn time that requires too much advance which causes the engine to be detonation sensitive and fuel hungry . While most rodders are carried away with port and valve sizes as the path to power, the subtle shapes of the combustion chamber are equally as important if not more-so toward power development. This is where the really important changes in the L31 head occur. The combustion chamber of the L31 head returns the lost knowledge of Sir Harry Ricardo to engine design. Over at Ford it's the GT40 head and at Chrysler the Magnum LA or Ram head. All of these heads push the spark-plug as far toward the center of the chamber as the valve location permits, introduce the so called heart or liver shape which provides dual side squish and quench for fine fuel and air mixing (squish) and an area of heat sink (quench) which builds detonation resistance. A beak is projected from the squish/quench deck between the valves to isolate and redirect intake flow from going out the exhaust valve during cam overlap. All this is long known technology from before WW-2. These configurations can be found used on the 1953-55 Lincoln Y block and the 1954-55 Ford Y block, in a somewhat simplified form on the 1955 to 1970 Chevy small block, as well as others. But gradually these features were removed by the finance cost cutters at the factory which had the effect of reduced engine efficiency and detonation resistance. The factory's figured that the cost they saved of a few cents per head which reduced your performance and increased your operating cost due to higher fuel burn rates, and the increased emissions into the environment could just be transfered to the end user. This worked into the mid 1980's when increasing government regulation on emissions and fuel mileage finally forced them back to original and more efficient design principles.

The incorporation of electronic fuel injection and Honda's stratified charge combustion chamber being the final irony as both are American inventions rejected by American manufacturers back in the 1950s. EFI was developed by Bendix using the then new transistor technology and offered as an option by Chrysler in 1956 and 57 but people were more interested in putting their extra money into air conditioning. The hugest irony is that the stratified charge technology used by Honda was developed by Texaco under a government contract with NACA (the predecessor of NASA) to develop a method to increase the range of bomber aircraft so that Germany and Japan could be reached by bombers from the continental United States should England and Hawaii fall into enemy hands.

Anyway 305 heads on 350's is old hat. The work and cost it takes to make them competitive against a comparably equipped L31 Vortec headed engine isn't worth the outcome. The money is better spent on L31 heads even for, and they will fit, a 305, just getting the valves into the cylinder bore, but just is more than good enough in this case.

Bogie
 
#10 ·
cobalt327 said:
Take a look at POST #478.

This entire thread is a good one, lots of Vortec info, mainly on the L31 5.7 heads, not the L30 5.0L heads, but good nonetheless.
Very good link. I've never anything bad to say about the 059's (probably because my DD is powered by an L30). It was definitely a decent powerplant for it's time and place. For anyone who's interested in some flow numbers, these are from the Stan Weiss flow chart:

Vortec L30 "059" casting:

0000 Int Ex
.100 68 47
.200 128 103
.300 179 138
.400 205 152
.500 221 163
 
#11 ·
Yes see, those flow numbers arent bad for a 305 head. But the real problem when using vortec with older EFI systems is in the base. It costs $450 bucks just to complete the combination. It all adds up to too much cash for the performance you get. I would be better off with some worked s/r torquers from world or maybe even the box stock TFS 175cc 23* head. Keep in mind I am simply trying a head and cam package on a LB9 305 for better performance. I choose the vortec head because we all know it flows better at lower lifts, which is where TPI likes to make power and TQ.
 
#12 ·
Reworked S/R Torquers?! You still need the baseplate and those heads will cost just as much as vortecs.

You gotta pay to play. How much you want to play? Why would you even bother with a 305 TPI? You could probably get a whole 350 TPI for a couple of hundred. What are you looking for, torque or hp? TPI is all about torque.
If you must stick with a 305 then....Stock vortecs will handle a cam like a Comp XE 256. Want more cam? Then get the valve guide boss cutters that will allow more lift. Pick a pair of vortecs up at the local yard for $200, get your vortec TPI base, and your cam and lifters for $150 and you will have gained 40 horses and torque down low for $800 (or less if you shop smartly, scoggin dickey has the price for baseplate at $399, now you're at $750). Cheap for the gains you make.
 
#13 ·
cool rockin daddy said:
Reworked S/R Torquers?! You still need the baseplate and those heads will cost just as much as vortecs.

You gotta pay to play. How much you want to play? Why would you even bother with a 305 TPI? You could probably get a whole 350 TPI for a couple of hundred. What are you looking for, torque or hp? TPI is all about torque.
If you must stick with a 305 then....Stock vortecs will handle a cam like a Comp XE 256. Want more cam? Then get the valve guide boss cutters that will allow more lift. Pick a pair of vortecs up at the local yard for $200, get your vortec TPI base, and your cam and lifters for $150 and you will have gained 40 horses and torque down low for $800 (or less if you shop smartly, scoggin dickey has the price for baseplate at $399, now you're at $750). Cheap for the gains you make.
Local junk yards have NO vortecs. E-bay is the next place, but thats about $400. I can get a set, worked for $700.00 with beehives, guide plates, machined for .600 lift, ls1 style valves.. NEW! I was told NOT to cut them down to 58cc chamber, because it would alter the chambers too much. IS THIS TRUE? I know about paying to play. I play for a living. Just wanted to know if anyone had some cheaper alternatives. thanks.
 
#15 ·
What about milling the head .036" to get the chamber I want?? If milling about .006cc off the surface ='s -1cc... A local machinist told me that that would not be a good idea. Honestly he didnt sound like much of a hot rodder. I can mill .024" thousands minimal for a 9:1 compression.
 
#16 ·
Third, do yourself a favor and get a good book on hotrodding chevy engines. You will discover that raising or lowering the compression ration does not make that big of a hp difference. You gain a whopping 4% hp increase with a full point increase of compression. On a 400 hp engine that equates to 16 hp. Milling heads has it's limits as you can mess up the angles of the mating surfaces between heads and intake manifold. Not worth it. Get Lingenfelter's book on "How to Hot Rod Small Block Chevy Engines".
 
#17 ·
cool rockin daddy said:
Third, do yourself a favor and get a good book on hotrodding chevy engines. You will discover that raising or lowering the compression ration does not make that big of a hp difference. You gain a whopping 4% hp increase with a full point increase of compression. On a 400 hp engine that equates to 16 hp. Milling heads has it's limits as you can mess up the angles of the mating surfaces between heads and intake manifold. Not worth it. Get Lingenfelter's book on "How to Hot Rod Small Block Chevy Engines".
Get a book huh? lol - thats funny! Everything else you said is well known info, im talking about VORTEC heads, and Vortec heads ONLY, no 2 heads are the EXACT same, especially when machining. 4% on a 215hp 305 is about 8.5HP, i'll take that! After modding it will be worth 15hp, well worth worrying about. I would also say a 8.2:1 305 runs like $#!t. I know about intake alignment issues, its fairly easy to fix by hand without hurting flow. Also, telling someone to get a book over a particular head question is BS. I hope you are just meant to help out and that wasnt meant as an insult.
 
#18 ·
No, it wasn't meant as an insult. However, your tone is increasingly becoming one where an insult would be deserved. I suggested the book because you are all over the map on your questions. First you ask about 305 vortecs. Then you start talking about vortec baseplate for TPI. Then you say you are bucks down. Then you talk about reworked S/R Torquers. Now you ask about milling heads. You sound like you DON'T have a plan, DON'T understand basic engine hotrodding, and you DON'T have any money. Am I wrong on any of those assumptions? If so, I apologize. If not, get the book I mentioned, read up on it, make a plan for your engine, and make a budget to make it happen. If that sounds like an insult to you or too harsh for your sensibilities, that's on you NOT on me.
 
#19 ·
Those numbers are killer for a factory 305 head... roughly 40cfm more on both the intake and exhaust than many other 305 heads, and for the most part, the pre-vortec, 80's and 90's 305 heads were better than a lot of the similar vintage 350 heads.

For that matter a friend of mine spent a few hours just doing some basic clean up with a carbide bur (no sanding or real heavy work), installed some 1.94/1.55 valves... they flowed 260intake, 222exhaust at .500" and made 460hp on a well built 350.
 
#20 ·
The 059s do flow well but I wouldn't take those numbers I posted as gospel. I didn't personally test them myself nor do I know the source from where they came from before they wound up on the Stan Weiss chart. I would consider those figures for "educational purposes" only.
 
#21 ·
No actually, its just not having a plan at the moment. I am not broke either, I am trying to do a 305 for once, seemingly how it will never run like a new LS3, or a coyote with any form of redeemable driveability. So I am shooting for mid 13's, to keep most imports at bay. Atleast, most honda/acura products. I graduated UTI, worked for Prewitt, then ProTech, then dyno operating at CCS, then (now) doing Top Fuel Hydro (#777 Disorderly Conduct) with family. I know cars, and performance, just NOT 305's with Vortec heads. From what I have gathered, the STOCK 081 castings are flowing 195/110. With headwork and a valve job its possible to make 240/155, which SHOULD be enough to take this 5 Liter GM in the 13's. Intake choice is going to be key, with a ported base thats siamesed, siamesed runners, and a port job on the plenum with throttle body, full exhaust and some 3.42 gears... I may have close to it. Add a stall and some trans work with a stick tire, and it MAY be there. Lets not forget the custom prom tuning... NOW... This IS simply nothing but a guesstimation.... I dont like gambling with a 305, or my money ON a 305... See how this can be irritating and warrant questions?
Silver, thats awesome! Pretty close to what i'm looking for...what do you guys think about the 1.94's in a 305?? Shrouded? Do you think some better valves with a nice seat job (4-5 angle) valve job in other words with some 1.84's would be better?? The cam is most likely a 206-216 .450 @112... something the TPI knows what to do with.. Maybe more but not much thats for sure.
 
#22 ·
Update: It hasnt been easy, every corner I turn, every guy I get a price from etc. etc. points to one thing... 350 swap. The best I can do, is to NOT spend any significant money on a 305 and do head porting and intake porting by myself. The EQ 305 heads flow about what stan weiss says, but they are in fact $715.00 assembled. Mix that with a vortec intake for $375 and it's a no go.
So- I bought a 350 vortec 882 block and crank. It needs new rods and pistons etc. but at least I wont be throwing my $$ away.
I figure a 355, flat tops, 270 cam, vortecs and a decent exhaust with TPI would get somewhere. The turd gen cars are so heavy, it should be mandatory anyway.
 
#25 ·
ThirdDegree said:
Update: It hasnt been easy, every corner I turn, every guy I get a price from etc. etc. points to one thing... 350 swap. The best I can do, is to NOT spend any significant money on a 305 and do head porting and intake porting by myself. The EQ 305 heads flow about what stan weiss says, but they are in fact $715.00 assembled. Mix that with a vortec intake for $375 and it's a no go.
So- I bought a 350 vortec 882 block and crank. It needs new rods and pistons etc. but at least I wont be throwing my $$ away.
I figure a 355, flat tops, 270 cam, vortecs and a decent exhaust with TPI would get somewhere. The turd gen cars are so heavy, it should be mandatory anyway.
I would consider a slightly smaller cam with TPI. Also you'll want a reverse split on the cam, like running a restricted intake.
 
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