will 350 head on my 305 give me more hp?I have a 86 carb z28.

 

no it will lower the compression ratio. 305 on a 350 will help a lot but not the other way around.

 

You will lose some compression if you go that way. Some people will do it, and claim that if the heads are good enough, the increased flow will make up for it. I'm not sure I agree with that though. If they are 64cc heads, with 1.94 1.50 or 1.60, they may be worth it, if they have been ported for flow. Personally, I would rather re-work the 305 heads. Remember though, if you put bigger valves in your 305 heads, you will be increasing the chamber size also, therefore losing compression. Its kind of a catch22. The only real way to get ahead is to drop the 305 and get a 350, but this isnt always a viable solution.

 

I see people say this alot but people never say what the chamber size is on a 305??

What is the chamber size on a 305?

Even all my books just read 305 head 87-92. On the 350 heads they say valve sizes and chamber sizes.

 

305's had 58cc combustion chambers, 350's (L98) had 64cc. Typically, when someone says 350 heads, they are trying to pawn off 76cc (882, 993, etc) crap heads. The kind of stuff that I would kick someones butt for dumping any where near my garage. The last time I took a set to the junkyard the guy there gave me a dirty look. They are bad.

An overlooked, but really good choice for a 305 is the l98 corvette heads. The corvette heads had 58cc chambers with the 350 sized valves. A good combo for a 305.

Sorry I skirted your question. 350 heads got 1.94 1.50 valves, and 305 heads got 1.84 1.50 valves.

 

They do however make really good door stops and wheel chocks.....LMAO

but seriosly i wouldnt put a set of 882 or 993 heads on a 305 or a 350 as lj said they are crap ...

if it were my car and I wanted to upgrade something it would be the exhaust it will open up alot on that 305 with headers and a good flowing system

 

Porting practice then a boat anchor. Works really well.

 

Yeah me and lj have a couple heads in my garage we are doing some heavy porting practicing work on now....

Practice makes Perfect....

 

Sure 76 cc heads are great on a 305.



A 305 with a blower on top.

Actually I was thinking of using a 305/76cc head combo for a farm feild well pump. The low compression ratio would probably be great in this type of application.

 

LT1 heads are 54cc, and that's a "350 head"

...but if you're asking questions about whether a 350 head will give you more power over a 305 head on a 305...don't even THINK about messing with LT1 heads on your car.