Head gasket sizing question

[cdorhout]

I bored my block out to a 86.5mm bore. I figure I now have to buy a new head gasket (I was running a Cosworth 86mm). Cosworth doesn't sell a 86.5mm head gasket. Would it be bad to run a 87mm head gasket with a 86.5mm bore? Or should I look for another brand that sells 86.5mm?

[BoostFab]

head gaskets are usually a little wider than the bore. you should be fine; i don't think you can find any aftermarket head gasket with exact bore size.. even the stock one isn't exactly on the bore either.

[Cjmartz2k]

head gaskets are usually a little wider than the bore. you should be fine; i don't think you can find any aftermarket head gasket with exact bore size.. even the stock one isn't exactly on the bore either.

x2

[jdmser]

You can also get Cometic to cut you custom bores for head gaskets they already make. That's what I plan on doing for the 24.

[cdorhout]

Thanks guys!

I'm building my RB30 right now, had everything lined up and ready for assembly and realized I forgot to get a bigger head gasket.

I really like Cosworth head gaskets, so I want to stick with them. Plus Darius' horror stories with Cometic, I'd like to stay clear of them if at all possible.

I'll order a 87mm. Hope they can overnight it! I want it running by this weekend.

[jdmser]

Despite Darius' experience with his Cometic head gasket I know a few 1000hp+ cars running around here that haven't had and problems with them. Of course they made sure to machine their head and deck before install.