Ferocity02

iTrader: (60)

Ok, when buying head gaskets, they usually have a bore and a thickness. I know the head gasket bore is supposed to be a little larger than the cylinder bore. Say I want to buy head gaskets for my 4.000" bore LS1 block. Would I go to Cometic and buy 4" bore head gaskets, or buy 4.01" bore head gaskets? Basically, when Cometic advertises their head gaskets, is the bore they show the bore of the cylinder, or the bore of the gasket itself? Thanks!

slow trap

iTrader: (22)

i just checked a set i have still in the wrapper,i just poked a small hole to check with my calipers and they are what they say they they are or slightly bigger.mine were supposed to be 3.910 and measured between 3.915-3.918 so i say they are the size they advertise.

Ferocity02

iTrader: (60)

So you ordered head gaskets for a larger bore than what you had, then the manufaturer added even more bore. Sounds like you are supposed to order head gaskets for your bore cylinders, ie 4" head gaskets for a 4" bore, and the manufacturer makes the bore on the gaskets a little bigger.

Anyone else?

Beast96Z

iTrader: (21)

Mike, order for a little bit bigger than your bore. You want the gasket at least .010" bigger, and more won't hurt. The 3.910" that cometic sells is for a stock bore of 3.898", so it's .012" bigger give or take a few. Depending on what your bore size is, get the next step up from that. I've seen people use the 4.125 Felpro's on stock blocks, but I wouldn't do that just because of the compression loss. Up to .030 bigger should be no problem.

Ferocity02

iTrader: (60)

Thanks Jason! I think the closest size to 4.125" is 4.130", and the next one up is 4.160", a little too large I suppose. I'd imagine the 4.130" gaskets will do just fine. These are Cometics, haven't looked at Felpro yet.

BTW, the shortblock will be built very soon, next couple of weeks hopefully. All I'm really waiting for is some money and the Warhawk heads to come out. If they aren't out by the end of summer I'll probably use the stock heads for the time being

slow trap

iTrader: (22)

i would think you should be able to get a set with a bore of 4.030 or so.i'm actually glad they are a few thou over since my bore is 3.905 and sometimes your gaskets aren't exactly centered.with a 4" or bigger bore the cr loss from a 4.125 or so gasket would be very minimal.

GuitsBoy

iTrader: (4)

Like they said, shoot for .010 to .030 larger than your actual bore.

koolrayz

iTrader: (26)

i asked cometic when they made them for me. they recomended .030 over bore size

dalejr8ls1

iTrader: (1)

what thickness are you going with, the .040's seem to be the most popular Cometic ran. I am going with the cometic MLS 3.910 bore and .040 thickness to keep it close to stock setup w/ compression and valvetrain numbers

383ss

iTrader: (14)

second that. that is what they told me too.