Ok, i have a f20c sleeved block. It has 89mm bore and i was wondering what headgasket would be best if i am aiming to hit 750-800 whp? i usually always use OEM stuff, but i heard a few stories saying with an 89mm bore, the thickness between the walls is thin and the oem and cometic hg blow. I was looking at the cosworth, but they only come in 88 or 90mm. the rep at cosworth said it would be ok to use a 90mm on an 89mm block. So my questions are:

1. Is the cosworth gasket a good option for my setup?

2. Is it really ok to use a smaller diameter hg than what the bore is on the block?
I know a bigger smaller bore gasket would create a hot spot and is a definite no no.

Thanks in advance.
Fadi

 

i went with the cosworth for my 88mm bore so hopefully its a good hg.. but the 90mm should b just fine

 

Have a look at SCE gaskets. Not sure what bore sizes they do standard but pretty sure they can fab a custom headgasket and their o-ring sealing is fantastic.

 

If Golden Eagle have it how is it OEM?

 

Ahh, got ya.

 

call cometic. they have 89mm f20/22 gaskets in stock for like 113 shipped. great oem thickness gaskets for a small over bore.