GM 12557236 head gaskets

[hbps1978]

I was wondering how many of the professional engine builders/machinists here have built a GMZZ4 - GM602/604 crate engine and used the GM 12557236 head gaskets? I'm wondering if these composite head gaskets need any Permatex high heat copper spray a gasket installed on them or if they are fine to use "as is" out of the package? I'm building my own version of a GM ZZ4 street engine for a weekend driver/cruiser. Thoughts on these gaskets? Thanks

[dfarr67]

I've used them both ways on a SBC- still running. ARP studs/GMPP graphite.

[BOOT]

I plan to use some sim composite gaskets on a sbc head swap and prob will copper spray the deck side since it's not worth removing and resurfacing, heads will be surfaced so we'll see if I feel like spray both sides of the gasket at the time.

[gramps]

Used many times on the 604 with and without copper spray no problems either way. ARP hardware for the washers.

[engineguyBill]

Gasket sealer is not recommended with composite head gaskets. Just make sure that the gasket sealing surfaces are straight and clean. Also make sure that the block threads and head bolt/stud thread are clean and dry. Use thread cleaning tools for cleaning the threads, not tap and die set. Torque the bolts/studs in several steps following factory recommended sequence and tighten the fasteners to the maximum recommended torque and NO MORE.

[Sumtingwong]

They seal up good without sealer. Absolutely no fun to clean up that gasket off of surfaces.

[midnightbluS10]

I believe those were initially indicated for Corvette engines with aluminum heads, hence there being no center cooling hole. As I recall, thats what I was told. I don't know how true it is or whether that's the reason there are no center cooling holes in that gasket set.