I'm replacing the head gaskets on my Z and I want to make sure I only have to do it once, so could you guys help me out and just point me toward the best head gaskets I can get?

 

I have been informed that the Cometic's are the best LT1 head gasket; however, they are pricey and MR Gasket 0.026" head gaskets [ MRG-5716 ] are supposed to be pretty good for about a 100 bucks less than the Cometic. $34.39 vice $130

Mike

 

When I blew a headgasket, I replaced both of them with new GM headgaskets(the ones for the F-body, not Impala) and new GM head bolts. I put those headgaskets through hell too- radiator clogged and got so hot on two occasions that it blew the cap off the overflow tank, lost a bunch of coolant, and eventually the block cracked before those headgaskets did.

The best way to make sure you only do it once is to make sure your cooling system is solid and in good working order. That and get the heads resurfaced and perfectly flat before installation.

In the new engine I have Fel-Pro 1074's if I remember correctly.

 

Be careful if you use the .026 Mr. Gasket one with the aluminum heads. It's really meant for iron heads. I saw a decked block/head motor blow one out the back of #8 on a dyno. There is a pretty substantial space between head bolts at the back on a sb. It's a slick way to get more compression, and some guys are doing it, but I would recommend the 1074 fel-pro one.

 

Cometics are very unlikely to seal well to unmachined heads and block, arguably the best gasket we have available but that does not make them always the right choice.

I would not recommend the factory aluminum head gasket at .049 it is way too thick, at least get the Felpro at .039 at lest it will get you a little more compression and is still meant for aluminum unlike the b-body gaskets or Mr. Gaskets both meant for irons even though a fair number of people sucessfully use them with the aluminums.

 

using them on my 355, spraying a 150 shot, no problems.

 

Couldnt have said it better. MLS gaskets (Cometic's) require a very fine surface ra finish.