Finally got my engine

[etg]

So I finally got my engine back. I didn't really specify what I wanted in the engine, I just sorta said gimme an engine that works to the guy. I gave him a 305 apparently, which he got a 350 core for but kept the 305 heads. What kind of hp can I get out of this? How about reliability? This is a low buck daily driver so there really isnt a need for performance, but I would still like a quick lil truck. Also, I bought an edelbrock carb, flexplate, fuel pump, distributer, and some other stuff from summit racing. I have everything to put the tranny and engine together and drop em in. YAY. Stuff is finally getting done, but slowly.

[Ole Blue 68]

So what did you wind up with, a 305 or a 350?

[67ChevyRedneck]

I'm not too good with motors.... but aren't 305 heads essentially 350 heads? The only real difference is with the piston bore in the blocks?

In terms of 350 vs 305 if you want a "quick little truck" you'll be much happier with the throttle response from the "350."

I had an 86 Z28 camaro with a 305 (kinda funny, huh?) and my old heavy truck with a 350 could smoke the camaro....kinda sad actually....

[Billla]

IMHO you really need to find out what CR and what cam you got - the only way to get the right components together is to know what you got from the builder. They should be able to provide the head cc, CR and the cam card. Without that, it's just guessing...

[68GenIII]

I think the 305 heads have a smaller chamber = more compression.

[Billla]

Originally Posted by 68GenIII

I think the 305 heads have a smaller chamber = more compression.

Depends completely on the piston, stroke, head gasket compression height, overbore, etc. Without knowing that stuff there's really no way to tell...

[68GenIII]

Originally Posted by Billla

Depends completely on the piston, stroke, head gasket compression height, overbore, etc. Without knowing that stuff there's really no way to tell...

Yes and no, the 305 head has a smaller cc combustion chamber.

[dirtball]

I think stock 305 heads have smaller valves too. I think it was a bore clearance issue.

[Billla]

Originally Posted by 68GenIII

Yes and no, the 305 head has a smaller cc combustion chamber.

Maybe I'm misundestanding your point, but without knowing the specific setup making a head change isn't a great idea. Typical 305 heads are 60cc, vs 350 heads of 64cc, 70cc, 76cc, etc.

As an example, if the engine was set up with 76cc heads with -4cc pistons for 9.5 CR , a change to a 305 head would give 11.4 CR...which isn't possible in a Gen I on pump gas. Yes, you get more compression...more than is streetable.

Vortechs are 64cc; a +4 cc change = ~-.5 CR. Vortechs require an intake change as well. Best heads for the $$$, and the best deal in the universe

"Camel Back" or "Double Hump" heads were available in both 64cc (1970 and earlier) and 76 cc (1971 and later) chamber sizes. If the engine was set up for 9.5 CR with a 60 cc chamber, a 76cc chamber would give 8.1...yech. Definitely agree that they're not bad heads for <= .500 lift; Chevy still carries them brand new w/64 cc chambers under P/N 88958692 :-D

Suggestion is to post the casting numbers and let's see what you've got...but I would still get a full build sheet from your builder otherwise you'll play guessing games every time you want to upgrade.

[Werewolf]

Sometimes budget guys will use the 305 head on a stock 350 to boost the CR if you're running a stock eco cam, just to get some more spunk out of the engine. An older 350 with a stock cam isn't ever going to see higher RPMs anyway, and the CR is low to start. What, 8:1? Anyway, they did it for better power despite the valves being smaller and max flow being reduced.

Better off, by far, with a new set of heads. That is, if you want to make real power.