headgasket

[zmm95]

So my block is bored .020 over, however im having trouble finding a 4.020" bore head gasket for my head swap next month, any suggestions? Wold stock size or slightly bigger like 4.030 or 4.040 work? Id like to go as thin as possible for a little compression bump

[Fastbird]

You need a slightly larger gasket anyway, I think a 4.025 or 4.030 would probably be fine, but I'm not an engine builder, lol.

[95ImpySS]

Yes I do believe that stock bore gaskets will work. I am running a stock gasket on a 355 punched 0.030 over. 4.030
Have you had the block 0 decked? Sometimes on not so perfect surfaces its better to run a thicker gasket to help insure a good seal. Just some food for thought.

[96LT1355Z28]

Most head gaskets I've looked at are 4.100 bore, you'll be fine with about any choice with a 4.020 bore.

[zmm95]

Alright, awsome guys, yes I have had the block decked, about 6k miles ago. I dont want the THINIST gasket avalible but somthing inbetween that and average thickness would do me good.
Its good to hear that just about any size will work for me, although 4.100 seems a tad large. Thanks for the super fast response by the way guys!
as far as brands go, what do you guys reccomend?

[96LT1355Z28]

Not trying to insult but I'm talking about the cylinder bore diameter (4.100) not gasket thickness. I've had good luck with the .026 thick Mr Gasket (5716) but it will leave a bunch of black crap on the heads and deck that needs to be removed if/when it's taken apart. I'm using felpro's (1074) now and they seem to be working fine.

[Fastbird]

I wonder how much dorking with the compression ratio that does when you have a 4.100 gasket on a 4.0x0 bore. Figure it's an extra .09 to .04 diameter on the bore.......gotta count for something.

[RamAir95TA]

I went through this awhile ago with my 383 build. The difference in compression is very slim. Many compression ratio calculators don't even have an input for the gasket bore.

[zmm95]

no insult takes as i am also talking about the bore. As fastbird said, its gotta count for somthing. I would assume its slim but hey, the smaller the bore, the further the cylinder sealing ring is from the water jacket, the less likely a blown headgasket will occur.

[95ImpySS]

no insult takes as i am also talking about the bore. As fastbird said, its gotta count for somthing. I would assume its slim but hey, the smaller the bore, the further the cylinder sealing ring is from the water jacket, the less likely a blown headgasket will occur.

Which is why people O ring the block and heads. You should be fine with the gasket unless your planning 500+ whp and huge boost numbers. If you want EXACT numbers. Make sure you calculate with the spark plugs in the head, the piston gap between the cyls. As ram air stated most people skip the extremely fine details because it only changes the comp ration by a comparable small amount.

[Fastbird]

Which is why people O ring the block and heads. You should be fine with the gasket unless your planning 500+ whp and huge boost numbers.

This. Exactly why my block was o-ringed.