Thread: Qust : 355 with 8.2 comp = 350HP?

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Can big 2.02 valves reworked chambers and 327/350HP cam give a guy 350hp? I thought you had to have a larger compression number.

Compression will be too low for that power... depends on many things so this is my guess. 1 HP/ci takes more work... My guess would be closer to 300 HP not knowing the specifics...

-Chris

Okay, I have fuelie heads off a Z28 Camaro. Pistons for a blower motor build are deep dish not flat not domed. If I can get 300 hp I would be happy.

"If I can get 300 hp I would be happy."

Not a chance. With 8.2 and the late intake closing point of that cam, you'll be lucky if the motor has enough power to pull the hat off your head.

First a 355 even with Dished Pistons and 76cc Heads has more then 8.2.1 C/R . Next the L-82 350s 1973-80 had 9.1 C/R and a Bigger Camshaft then the 327-350 HP #151 Camshaft . They also had 2.02 / 1.60 Valves . The L-82s I had Ran very Strong right out the Box I have built SB Chevys with 8.75.1 that ran 13-Teens with auto trans 3.42 Gears . I know the cam that works real good with the Lower C/R SB Chevys COOL

No problem, just put a blower on it!

The 327 350hp L79 cam had single pattern duration of 222 degrees intake and exhaust, 0.447" lift intake and exhaust and was ground on a 114 degree lobe separation angle.

With 8.2 static compression ratio, this cam will result in 7.2 dynamic compression ratio. For this cam to work properly, the motor will need 9.5 to 10.0 static compression ratio. If you're gonna retain the blower pistons, back off on the cam. Or retain the cam and change pistons.

Good luck.

Again a 355 with Dished Pistons and 76cc Heads has More then 8.2 C/R . How about if the Block was Decked ? And Like always when heads are Rebuilt -0.10-0.20 True-ing up cut ? 0.15 Head Gaskets . Now your near 9.1 C/R . Like I said I know of a Camshaft that works real well in the 8.5.1-9.1 C/R SB Chevy builds . Tech Were are you Coming up with your C/R #s ?? I ran many different Heads / Pistons / Gaskets / I can Tell you in Real World SB Chevy Builds what Octane Gas you Need to use . Don't Let that Math make you run 92 Octane Fuel when you do not want to . As for the L79 cam GM#151 Back when we did not have all the Camshafts Like Today . I ran that and the L-82 Camshaft in 9.1 C/R 350s with it advanced 4-degs . The cars Raged and ran real good on 89 Octane Fuel . Yes Today there are Better Camshafts and I do think it is best to CC your heads and Piston dishes . This way you will Really now what your C/R is .

If the guy sez he has deep dished blower piston and the compression ratio is 8.2, IMO it's safe to assume that is what he has..... Pistons are available that will render that and even lower CR's......

Originally Posted by Dave Severson

If the guy sez he has deep dished blower piston and the compression ratio is 8.2, IMO it's safe to assume that is what he has..... Pistons are available that will render that and even lower CR's......

The Guy never said he had Blower Pistons ? Tango said Do the cc-ing Friend ? Oh most SB Chevy Blower Pistons are set up for 7.6.1 C/R

Originally Posted by tango

The Guy never said he had Blower Pistons ? Tango said Do the cc-ing Friend ? Oh most SB Chevy Blower Pistons are set up for 7.6.1 C/R

Read post #3... I'm sure your experience in building blower motors exceeds mine, I've only done 1, but I ordered the pistons with the dish that I wanted and that's how they were made.....

Ok Blower Pistons D-Cup -22cc with 64 cc chamber heads and 0.15 Head gaskets with an +30 over Bore 350+ 355 wil have 8.7 C/R . Do some CC-ing so you know for sure where you are at . Them 64cc Fuellys may be 60-62 CCs by now .

Even a Comp HE 268 cam will out perform the old L-79 and L-82 cams, especially when used in a low cr motor. If you want a really nice low-mid range cam and a lopey idle, try the Crane 274H06 218-218 .454-.454 lift 106LSA. Valve events are 7-31-39-(1)@ .050. My buddy just put one in his 260HP 350 Gm crate motor that has maybe 8.5 cr at best and he loves the cam. Car is a 81 Vette with a 4 speed, 3.73 gears, headers, edel. intake and carb. You may need a 2000 stall with an automatic and highway gears.