Very good luck with MLS gaskets here but your block and heads will need to have a very smooth surface finish, 32 RA or less for Cometics (the Fel Pros have a thicker coating and additional sealing beads around the coolant ports and will tolerate up to 55 RA or so they say.) Any halfway decent machine shop with equipment in good shape and a guy who knows what he is doing should have no difficulty achieving a finish that meets the criteria. After some tweaking at my friends shop we are getting surface finishes averaging in the 16 RA range using his Berco surfacer using a single point cutting head with a PCD insert.
I was previously running the Fel Pro "performance" gaskets with the pre-flattened SS fire rings and had no problems with them at 15psi but went to Fel Pro MLS gaskets this time around for some peace of mind. Also, the metal gaskets (copper and MLS) are more efficient at heat transfer between the head and the block and will help dissipate hot spots better than a standard composite gasket.
The other nice thing about MLS gaskets is being spring steel they have some give and when the head lifts a bit from excess cylinder pressure (i.e. detonation) they will resist blowing out.
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1969 Chevelle
Old setup: Procharged/intercooled/EFI 353 SBC, TKO, ATS/SPC/Global West suspension, C6 brakes & hydroboost.
In progress: LS2, 3.0 Whipple, T56 Magnum, torque arm & watts link, Wilwood Aero6/4 brakes, Mk60 ABS, Vaporworx, floater 9" rear, etc.
Last edited by Blown353; 07-19-2006 at 04:08 PM.
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