the five liter family

[1980c10]

I currently have a 250 inline six in my '80 2wd swb 4 speed truck. I had a 305 in my '82 lwb 4x4 4 speed truck with 31x10 tires and i got better power and mileage out of the 82.  17mpg with the 250 and 18 with the 305 in a bigger taller heavier truck. go figure. I am considering finding a camaro 305 and seeing what kind of mpg's i can get. I don't need to be really fast just don't want to be really slow either. but most of all i want to drive it without stopping at the gas station everyday. oh by the way both were mostly stock engines.

[VileZambonie]

Obviously, on a totally stock engine, namely a 305, you don't want to get to crazy with the boost;  i'm thinking (will do more research) 14lbs in very occasional short spurts would be ok if we assume a stock compression ratio of 7.5 to 1.   Up to 7lbs should be ok all the time.

i think high RPM is way more detrimental than pressure on the pistons/rods/crank etc.

Will clarify further later;  Too tired now.

So once again why would you waste your $ supercharging a 305 when it would cost the same to supercharge a 350?

[Stewart G Griffin]

No, i agree;  IF you were going to take the engine apart and put in forged pistons/rods/crank etc. to make a serious supercharged/turbo'd engine the yes, it would most probably be easier/cheaper/better to start with a 350.

But i was talking about totally bone-stock;  Just take the stock intake off, bolt the blower on and then put the quadrajet, or whatever carb you're going to use back on, and go!  In this case, i think you could have a very surprising perfomer without too much work or money relatively speaking.

UPDATE:  6-71 blower actually cost closer to 3K.  But think of the time savings---install blower vs. change cams/compression/heads etc.

[78 Chevyrado]

From what I've read here and there, other than less cubic inches, the main reason 305s aren't used much is lack of aftermarket heads available.  350s are used so much because practically all aftermarket parts are engineered for them. 

That little 302 was a bad*** engine though, I'd take one no problem if I had an old camaro to play with.

[Layne]

I wonder why the 302 vs the 305 is such a big difference? Heads? EPA? Different eras of motors in vehicles?

[SUX2BU99]

Block-wise, I believe it was bore and stroke. 302 was an over-square motor, with large bore and short stroke = Hi RPM screamer. Couple that with large-valve heads, a cam to match and a good-flowing intake and you have a revver which worked well with 4.xx+ gears and a lighter car. 305s were always saddled with crappy heads, cam and intake plus they were small bore. Yeah, different eras to contend with.

Put a 302 in one of our trucks and you probably wouldn't be too happy with it.

[Captkaos]

305 were built for economy.  302 was 1 cube under the max size for 5.0L engine for the race series, you can make a 305 have power, but if you were chosing a motor to build for power and weren't limited to size, naturaly you will chose the largest possible.

[fitz]

Put a 302 in one of our trucks and you probably wouldn't be too happy with it.

Personally I would sell off the 302 for big $$ and then would have the money to buy just about any crate motor out there that GM makes.

[malibu795]

can a 305 be God motor sure..

cam swap would make a world of difference even a comp 257H cam woudl wake these things up

i degree a stock 305 cam once 168* intake 175* exhaust  lift at vlv as .325/.375 I/E and a 105*lsa
manifold nice dual plane
exhuast
carb
headers
even heads would make a difference

and you know what all that is swapable to a big inch SBC

 geting 250-275hp out of a 305 is not hard