Decking 3500 Heads with MLS Gaskets

[G.I.Ceo]

Does anyone know how much I should have my 3500 heads decked for using .070 MLS to keep the compression inline?

[3400-95-Modified]

.060 is standard headgasket thickness... is this on a 3400 block? If so then I don't think you can deck them far enough to get the 9.5:1 if its a stock 3500 block then I would guess .010 would do it. But why not just get .060 head gaskets?

[ForcedFirebird]

I would be more concerned with the mill finish than the ever so slight difference in compression. You need to tell your machinist to finish them to 50ra or better to avoid leaks.

[G.I.Ceo]

I would be more concerned with the mill finish than the ever so slight difference in compression. You need to tell your machinist to finish them to 50ra or better to avoid leaks.

Now what do I need to do on the block part to make sure that sealing end will be ok too? I found a shop to take care of the decking on the cylinder heads. Now I am wondering on the block end if that is going to seal ok. Would I might be better of to just not use the MLS gaskets for my boost setup and revert back to stock head gaskets or just push forward?

[TGP37]

I've heard of some using stock gaskets with great results. I read some consider the stock gasket like an over boost fuse, better blow out the gasket instead of a piston.

I boost up to 12 psi on stock head gaskets and all is well. I believe the MLS is best for an engine that will be taken apart a lot.

[ForcedFirebird]

Now what do I need to do on the block part to make sure that sealing end will be ok too? I found a shop to take care of the decking on the cylinder heads. Now I am wondering on the block end if that is going to seal ok. Would I might be better of to just not use the MLS gaskets for my boost setup and revert back to stock head gaskets or just push forward?

We have had great success by drilling out the rivets and spraying the layers with copper when both surfaces don't have fresh machining.

[G.I.Ceo]

Yeah I have heard people talk about doing that. They said it's a must to spray the gaskets with copper spray or pretty much your guaranteed to have them leak. So do you think I should still have the heads decked or just do what your suggesting? I planned on spraying them either way.

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[SappySE107]

The block is probably ok, the heads are probably not. I would mill the heads no matter what you do.

[TGP37]

After thinking about the above post, I must agree with SappySE107, being the block is iron and the heads aluminum, the heads will experience greater expansion/contraction against the MLS gasket.