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327 build

6K views 39 replies 11 participants last post by  MouseFink 
#1 ·
im taking my 327 block to get bored out 30over, looking for a 331ci final size. this will be an old style fuel injection motor when done. block came with a steel crank which needs a good cleaning and polishing. does anyone know what size diameter is the small journal, i want to check the size. also thought about getting a new Scat crank instead of spending money on the old one, any thoughts also pistons and rods and rings, on a budget. thanks
 
#5 · (Edited)
Scat 2-ICR5700P rods, I-beam, pressed pit pins, 5.700" cc, 12 pt bolts.
Speed Pro Pistons, L2165F30, forged flat top, 4-valve relief .030" os, 4.030" bore, fitted to each respective cylinder with .0035" clearance, pressed fit pins, 5/64" top, 5/64" second, and 3/16" oil rings

It is customary for the crank grinder to furnish the rod and main bearings and you specify the brand and type. Plastiguage or use a micrometer on the journals after you get the crank and bearings from the grinder. If you buy a new Scat crank, you should furnish the standard size bearings.
 
#6 ·
does anyone know what size diameter is the small journal, i want to check the size.
Small journal cranks are 2.300" on the main bearing journals and 2.000" on the rod journals........ 0.010"-under rod journals would measure approximately 1.990", 0.020"-under would measure approximately 1.980" and 0.030"-under would measure approximately 1.970".


also thought about getting a new Scat crank instead of spending money on the old one, any thoughts also pistons and rods and rings, on a budget. thanks
If I had a small journal forged crank, I would magnaflux it for cracks, then polish it and use it.
Here is the Scat forged rod to use with the small journal crankshaft.....
https://www.summitracing.com/parts/sca-2570020-sgl/overview/make/chevrolet
I would purchase new rods instead of spending money on re-furbishing the old fatigued ones.
 
#37 ·
Small journal cranks are 2.300" on the main bearing journals and 2.000" on the rod journals........ 0.010"-under rod journals would measure approximately 1.990", 0.020"-under would measure approximately 1.980" and 0.030"-under would measure approximately 1.970".



If I had a small journal forged crank, I would magnaflux it for cracks, then polish it and use it.
Here is the Scat forged rod to use with the small journal crankshaft.....
https://www.summitracing.com/parts/sca-2570020-sgl/overview/make/chevrolet
I would purchase new rods instead of spending money on re-furbishing the old fatigued ones.
thanks just measured and 2.3 and 2.0 almost dead on, need to claen the surface rust from sitting for so long. i'm going to find out how much the polish the crank and have it checked compared to a new one. thx
 
#8 ·
Listen to Buzz regarding domed pistons. Also, small combustion chambers means even higher compression. Keep your static c.r. below 10:1, especially with iron heads.

If this is not a race motor on race gas, today's pump gas should figure into your build on your build. Don't be star struck by exotic cam grinds
 
#9 · (Edited)
.Shopping list for my 1962 SB Chevrolet 327+ .030" os (331 CI), 1962,double hump 64 cc heads, 1.94" I / 1.50" E Ferrea SS valves, PC positive stop valve seals, K-line phosphor bronze valve guide liners

Pistons................Speed Pro L2165F30, flat top, 10.3:1 CR, forged, 4-valve reliefs
Rods.................. Scat 2-ICR5700P, steel, 5.700", pressed pin
Camshaft: ......... Comp Cams 12-671-4 Nostalgia Plus or GM 3863151, 327/350 HP, L-79 (discontinued)
.468" I. .462" E. Valve lift
229 deg. I. / 226 deg. E Duration @ .050" lifter rise
110 deg. I. / 118 deg. E, LSA
Lifters: ............... Sealed Power HT-817 w/ HD C-clip PR seat retainer
Valve Springs....... Pioneer RV-943X, 115 lb @ 1.700" / 290 lb @ 1.232"
Pushrods ............ Comp Cams Hi-Tech,7993-16, 7.900", chromoly, 5/16"

A 3600 lb car needs a 4-speed manual, 3.70:1 or 4.11:1 cogs and tires with good bite.

Or get a bigger boat.
 
#10 ·
Lifters:

Use Sealed Power HT817R short travel Hi Rev lifters if you are considering weekend Dragstrip events, especially with 4.11:1 gears that will get you to the shift points quicker. The Sealed Power Hi Rev lifters are worth an extra 500 RPM with Pioneer RV943X valve springs and the Comp Cams Nostalgia Plus camshaft. Shift points with the Hi Rev lifters will move from 4,500 RPM to 5,000 RPM and valve float will occur at 5,300 - 5,500 RPM and will act just like a kill-switch.

The Sealed Power HT817R lifters set from .002" - .005" preload and for that reason, they have a heavy duty C-clip pushrod seat retainer. They also have a hardened face for high spring pressure and no lead motor oil. The hard face is indicated by a groove around the bottom of the lifter. The standard HT817 hydraulic lifter preload is . 065" or half travel and they do not have the hard face? Those lifters will pump up and float the valves at 4,500 RPM. Since the Sealed Power HT817R lifters set at .005" preload, they have no where to pump up to.
 
#11 ·
Lifters: Use Sealed Power HT817R short travel Hi Rev lifters if you are considering weekend Dragstrip events, worth an extra 500 RPM with Pioneer RV943X valve springs and the Comp Cams Nostalgia Plus camshaft. Shift points with the Hi Rev lifters will move from 4,500 RPM to 5,000 RPM and valve float will occur at 5,300 - 5,500 RPM and will act just like a kill-switch.
The standard HT817 hydraulic lifter preload is . 065" or half travel and they do not have the hard face? Those lifters will pump up and float the valves at 4,500 RPM.
WHY do those RPM numbers all look so LOW ???
 
#13 ·
mouse made a typo

the exhaust duration is 336º not the posted 226º

no camshaft needs a specific rear gear ratio. They are not related to the power of the engine. The rear gear ratio combined with the transmission ratios determines where the car will perform its best. Steeper rear gears are more for drag racing. If you autocross,road race,highway cruise, they all need different rear gears/transmission ratios and of course the wheel and tire size to match application of "car".
 
#14 ·
The lower rear end gear ratio replaces lost low end torque of a longer duration camshaft.

In simple term, as the valve duration goes up, the rear gear ratio should go up, unless you plan on speed trials on the salt at Bonneville Speed Week.

There is nothing more annoying than driving a engine with a radical camshaft with freeway flyer rear end gears.
 
#15 · (Edited)
Raise the shift points, add this:
If you want 7,000 RPM shift points add the following to the shopping list:

Intake manifold, 1967 -1970 GM, Q-jet
Carburetor, 1967-1970 Rochester Q-jet, air valve secondary, 800 CFM
Camshaft, Comp Cams 12-107-3 solid lifter "30-30" classic FI single pattern
.485" valve lift
254 degree duration @ .050"
114 LSA
Lifters, Comp Cams 800-16 EDM, solid
Valve springs, Comp Cams 941-16
130 lb @ 1.750" / 350 lb @ 1.265"
Break the cam in with Comp Cams 981-16 valve springs then switch 'em.

10.3:1 compression ratio, 93 octane no lead pump gas. EXXON/Mobil preferred

4.11:1 or 4.56:1 rear gears for optimum acceleration from a traffic light.

Sorry, No freeway flyer,, gas economy granny gears with this set up.
 
#16 ·
worst case scenario
2.73 gears,,, 2.5 first gear.
26 tall tires
@ 1400 rpm you are going just over 15 mph,round up to 16 mph

3.73 rear gears
all else the same
you are going 12 mph

pretty close
Just stomp it and away we go

the steeper rear gears will launch the car harder with racing tires and will improve your E.T. by 2-3/10s only.
even a stock stall converter will stall 1600 rpm.
A racing converter will cut 4-5/10s with racing tires.
if you have a really small engine and a heavy car you wont be drag racing it without racing tires/converter/trans&rear gear combo.

why do you think the engine will lose torque? It should gain torque with hp but at a higher rpm. Standard transmissions usually have an extra gear,,,do the math
I ran my Corvette with 2.73 gears for quite awhile.Tires just break loose when you apply too much power.
If you "drag race" then rear gears might be part of a combination to perform that duty
 
#17 · (Edited)
Factory production cars:


You could not get a 1969-1970 Pontiac Ram Air IV with anything but 3.90:1 or 4.11:1 Saf-T-track, only available with a TH-400 or a 2.20 low 4-Speed Muncie.
1968-1970 Chevrolet Z-28 Camaro, 30-30 camshaft, 4.11:1 gears only..... No freeway flyer gears with that car.

My 1969 Firebird 400, 4-speed 2.54 low, 4.33:1 Saf-T-Track, Crane ZIP-510 solid lifter cam, GoodYear 8.50x/9.00X15 / 32" x 11" wrinkle wall slicks, BB Chevrolet L88 valve springs, Ram Air IV valves.
13.00 flat ET, , closed exhaust, stock frame, Rochester 800 CFM Q-jet, 10.5:1 CR, 6,500 RPM shift points, 428 HO exhaust manifolds............ 11 miles per gallon, 4,000 RPM on the freeway in winter, overheated above 3,500 RPM in summer.
 
#18 ·
Z-28 has a little 5 liter engine.
speeds in gears,,,64,,,85,,,111,,,140 plus on Belted non radial tires. That's a very good selection of matching the close ratio Muncie with 4.11s.
My 67 Camaro z-27 came with 4.11s and an A.M. radio, no other options.

we have much better intakes and heads now. A big cam is no longer an issue. My car ran high 11s in the 70s with cast iron heads,daily driven.

my statement is,,,its ridiculous to recommend a rear gear change without knowing the transmission,,, the wheels and tires,,,the application of the car.

My friends 66 Cobra has 3.5 gears and a 4speed 427 s.o. but the tires are 24 inches tall.
He needs a 5 speed or 2.73 gears
 
#20 ·
Another advantage of 4.11, 4.33 or 4.56 gears is they will permit the use of 29" -32" diameter rear tires for optimum traction. The only disadvantage with those gears is overheating the motor cruising at highway speeds. It is frustrating to drive along at 40 MPH on the freeway with the trucks and busses. I realize that is not modern thinking with the current no lead, low octane pump gas at two or three bucks a gallon. I have a Honda Pilot to use as a grocery getter and it gets 27 MPG.

I have a 3.36:1 positraction in my 1962 Chevrolet Bel Air 327/350 HP L-79 engine with a Borg-Warner T10 4-speed. I nearly pulled the trigger for a correct 1962 4.56:1 Positraction on E-bay at $1,500, plus shipping. I am going to hold out for a 4.11:1 Positraction, if it is not too long. My Chevy has the original Harrison radiator and it does not have a overheating problem yet.
 
#25 · (Edited)
Before 108 octane leaded gasoline was eliminated, an associate was searching for high octane booster for his 1957 McCullough supercharged Studebaker Silver Hawk. He heard that some kerosene in the tank would help raise the fuel octane. He put some in his fuel tank and blew a hole in a piston. He never said how much kerosene he put in the tank.

I use EXXON/Mobile Premimum at relatively new filling stations. That gasoline has Techron and that is a good fuel system cleaner. I use in my 2005 Honda Pilot and 1991 Chevrolet Blazer 4.3 L V6 and it actually seems to keep the injectors clean and the engines seem to run better. The computer controls the timing advance and prevents detonation on low octane pump gas.
 
#26 ·
Before 108 octane leaded gasoline was eliminated, 1957 McCullough supercharged Studebaker Silver Hawk. He heard that some kerosene in the tank would help raise the fuel octane. He put some in his fuel tank and blew a hole in a piston.

I use EXXON/Mobile Premium at relatively new filling stations. That gasoline has Techron and that is a good fuel system cleaner.
If he blew a piston on 108 octane plus kerosene, he may have been turning the boost up way too high... but we do things like that... my '62 Olds Jetfire with stock turbo charged V8 also blew a hole in a piston by 100,000 miles...

Gasoline companies like to put fancy names on additives that most or all gasolines have... Shell advertised the hell out of Platformate Mileage ingredient in their gas back in 1960's... turned out all gas had it, but by a different name... Shell doesn't want you to know they are actually Royal Dutch Petroleum Company... BP would prefer you didn't realize they are British Petroleum...

My one boat has 10.4:1 compression ratio, I've been adding 2 ounces of kerosene to the 40 gallon tank for 25+ years to stop the spark knock it was having at WOT without it on 94 octane at proper ignition timing... I just have an old red plastic 12 oz. octane booster bottle I keep in it filled with kerosene that I buy by the gallon in a larger container at the local gas station... If I get occasional spark knock or dieseling from 'bad gas' in other vehicles, a touch of kerosene also cures that until I get another fillup from a different station...
.
 
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#29 ·
Isnt kerosene about 80 octane just like number 1 diesel.
Some of those little 12 oz bottles of octane booster for sale contain nothing but kerosene, but that's an expensive way to buy it... can almost buy a gallon for what those little bottles cost... then refill the little bottle for the trunk... which is good for about 12 fillups...

Diesel is for engines with 16 - 22:1 compression ratio... and for jet engines... it's less volatile and safer than gasoline...
 
#40 · (Edited)
The GM 3863151 hydraulic lifter camshaft for the 1965 Chevrolet 327/350 L79 engines was discontinued by GM sometime between 1998 and 2000. Comp Cams and other aftermarket cam grinders immediately started producing duplicates of the "151" camshaft.
.447" valve lift
290 deg. Adv. duration
222 deg. dur. @ .050" lifter rise
114 deg. LSA

In 1967, the 350/350 L82 and L46 engines received the GM 3896962 camshaft.
.450" I / .460" E valve lift
292 deg. adv. duration
224 deg. Duration @ .050" lifter rise
114 deg. LSA

According to reputable sources, in 1968, Zora Duntov fought against deleting the L79 camshaft for the 1969 L46 Corvette engines, and wanted them with the L49 camshaft. The Corvette L46 engine was only available with a 4-speed manual transmission with the "962" camshaft.
 
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