Anyone know the dimensions of the stock head gasket for the aluminum head L98s. Fel-pro 1010 is 4.166" x .039" Seems to be to much for a 305 and not planning any major milling.

 

the stock size won't be far from felpro's, no more than .1" up or down. consider that a 305's bore is 3.735" and a 350's is 4.00, if you're going to put 350 heads on, use 350 gaskets so they're not sticking out into the combustion chamber.

 

A stock is 4.166 as well? I would appreciate it if some could post the numbers if they know them.

 

sorry i dont know stock size but just think about it, at 4.166" there's only a .083" gap between the edge of the gasket and the rim of the cylinder. If you get a smaller gasket, like for a 305, it'll be exposed to the flame because the combustion chamber is 4" wide.

what are you trying to do? do you want to put 350 heads on your 305? search on the topic, other people have done this. if you're just asking about gaskets, use 350 gaskets.

 

Yes, L98 heads on a 305. I know I need to use 350 gaskets. There are different size gaskets available for a 350. I am trying to find one that works my with components and machining. All I need are the dimensions and I can find which one will give me the compression ratio I am looking for. If one does not exist, I will have to consider milling the heads.
I will try this - Does anyone know of a gasket for a 350 with aluminum heads that has tighter dimensions than the 1010?

 

i've got the aluminum L98 heads on my car and i'm using ROL gaskets, i think the part number is something like HT31000 with a couple other letters on the end, it's their high end one that's ok for aluminum heads. I can't rember their dimensions but you can call and ask. I'm pretty sure it's .041 compressed but i dont know about bore. you might have a hard time finding an uncommon gasket size, especially on a gasket that won't brinnel your heads.

i'm still unclear on your goal here. Do you want to raise compression to increase power? if that's the case, try looking for a thinner gasket, not just one with a smaller bore. you should list the work already done to your heads and exactly what you're trying to do.

 

Ukraine Train, can't you just stop this? All I am looking for is if someone knows of a gasket that has tighter dimensions (bore and/or thickness) than the 1010 that I do have the numbers for. Not that difficult.

 

don't take it wrong, i'm just trying to help you out.

i'm *assuming* you're trying to get as high a compression as you can. if that's the case, i wouldn't worry about the gasket all that much, the difference between a 1010 and say a 4.066x.030 is maybe three tenths of a point of compression which is probably 5 or 6 hp.

i'm just trying to tell you that you might have a hard time finding a large selection of gaskets that can be used on aluminum heads, nothing more and nothing less. the reason i said to post what you're trying to do to your engine is because someone may have (and probably has) done it and they can help you out.

 

That's it. I estimate 6 hp just by using your example numbers there. With my setup its a .32 increase in comp. ratio. I can safely do that. Since I need to buy gaskets why not take 6 hp if you can. 6 here, 4 there, 3 while you are doing this and 7 while you are doing that, and before you know it you have 20 extra for little more than making a few simple yet strategic purchases or alterations.

 

good point. i took a look at summit's site, check this out:

http://store.summitracing.com/partdetail.asp?part=19099
http://store.summitracing.com/partdetail.asp?part=2430
http://store.summitracing.com/partdetail.asp?part=2492

felpro also has a .015 shim but no one recommends using them

 

Check out GMPP they have a couple for alum-heads the bore is 4.100 comp thickness .028 and .038

 

e-man beat me to it. I was going to suggest the stock GM gasket. It fits the chamber better than the FelPro 350 gasket. Make sure you get gaskets for the Corvette L98, and they should compress to 0.031". Sorry, I don't have the GM part number for aluminum L98 heads.

 

I have a set on my Vortec headed 305 at this time. $34.87 last Oct from GM Partsdirect


PN# 10105117 for the 350 bore and 10105115 for the 305 bore.

I used the 350 gasket since I had the wider chamber 350 heads.

 

I ran into the same problem, after a lot of seaching The smallest I could find was a 350 with 4.060/.035 made by Fearra; it had the the smallest combo of bore and thickness.