I'm trying to determine what or whose head gaskets I need to use. I'm using GM's Signature Series aluminum heads, 110cc chambers & 2.25 valves. GM sells a gasket for $75 with a 0.039 compressed height.

Felpro sells the 1027 for a 4.32 bore, 0.039 and 4.54 bore??? :confused:

Another guy tells me to use the GM L-88 gasket for $18.99 but GM says they're no longer made???

Anyone have any ideas on my 454 +0.060??


Thanks
Len

 

Len, a stock 454 bore is 4.25", your .060 over is 4.31", so a 4.32" Felpro will work fine. The 4.54" gasket is for a 502 style block, you don't want that.

To know which thickness you need, you would have to know the deck height of your engine. The stock "spec" is 9.8", but most engines from GM are actually about .020" or so taller than that. Basically, when the piston is at top dead center, you want to check how far down in the bore the flat part of the piston is. Usually, unless the engine has been decked you'll find that the piston is around .020 "in the hole". For optimum detonation resistance, you want the total of your "in the hole" measurement and the gasket thickness to total around .045" or so (called the "quench height"). If your piston is .020 down, and your gasket is .039, you have .059" of quench height. Kinda high and not optimal, but lots of engines came from the factory that way.

The $18.99 GM gasket is probably the copper gasket that they used to sell. The main benefit of that gasket for you would be that it's only around .020" thick, so even if your pistons are .020 in the hole you could still get a good quench height. I would go with a composite gasket for your application, less to worry about. Copper gaskets can sometimes seep.


[Modified by Flareside, 10:20 PM 6/3/2003]

 

Thanks for clearing that up Joe. I was wondering about the 4.54 gasket. I knew my bore was 4.31 but wasn't sure if 4.32 was enough clearance.

My deck height is at 0.010, so I should be around 0.049 quench.