will 350 heads on my 305 lower my compression ratio? what are some benefits/disadvantages to putting 350 heads on a 305?

 

Put aluminum ZZ4 heads on it and you will be doing great.

 

from what everyone has told me no 350 heads work on the 305 apperently something is differant about a 305 compared to other small block chevys like 302/350 and the like
as you note when looking in any parts books 305 heads are listed seperatly from all other small blocks

and i still havent found anyone that made 350 heads work on a 305

i was going to get vette 350 alloy heads but was told they wouldnt work by mechanics and just about every one i know and being that the zz4 heads are the same as the vette heads that most likey isnt a good idea

 

all 350 heads will bolt onto a 305. You have to watch out on the valve lift because the larger valves can and will hit the cylinder bore.

Other than that most of the 350 heads have larger (and sometimes much larger) chambers which drops the CR drastically unless you are going to use domed slugs.

 

oh i knew they would bolt up but that was one of the problems the valves would hit the pistons and also the compression
that to me made me shy away from 350 heads

 

Well whoever told you 350 heads wont work on a 305 was wrong.

There's a ton of people on this board who have used 350 heads on a 305. Its not rocket science. However due to the typical loss of compression ratio, I wouldnt advise it for most people. The ones that will find them useful are those changing the pistons while they are at it.

 

It could be useful if you plan on ramming 30psi of boost into it...

 

thanks for the quick replies guys! so from the sound of it, 350 heads arent really an option for me. im on a really tight budget, i just know that 350 heads are plentiful and relatively cheap. looks like i should stick with my own breed.

 

the over hang from the large combustion chamber could possibly cause hot spots and detonation. the best way to lower compression in a 305 is to run dish pistons and a good .041" head gasket. also, you may want to check out the 113 casting aluminum vette heads. they disipate heat a bit better and will allow you to run more boost on the same static c/r cause they have the same 58cc combustion chamber.

 

judging by the budget, i'm guessing you aren't doing forced induction right?

You just wanted better performing heads for your 305? Better than your TPI heads? 416's or 081s would do the trick, port 'em up!