Head gasket recommendations for magnum

BTW, with the critical nature of the P-V clearance here, I'd re-check that clearance for a couple of reasons:

• You put the head on the block without a head gasket. That will reduce the P-V clearance by the gasket thickness multiplied by the rocker ratio. In other word, you have reduced the P-V clearance by approximately .080" by leaving a .050" thick head gasket out.
• If you have hydraulic lifters in there, you have a chance that this will show a larger P-V clearance than when running if the lifters have leaked down any. You have to duplicate the actual running compression of the lifter to be accurate.

FWIW.. .the 814 piston CH is not all that much taller than any other 318/5.2 piston out there (except for certain older type low compression truck engine pistons). These all vary within about .020-.030" in CH. It is the lack of eyebrows primarily, combined with the .015" lower Magnum deck and the .020" deck milling and an unknown amount of head milling. Eyebrows on aftermarket performance pistons are typically .220-.280" deep so this problem would be unexpected for those using such pistons. And even the smaller eyebrows on 318 pistons are about .100" deep.

You might as well use a thicker head gasket... no quench is gonna happen here. You can buy Cometics to .100" or thicker. How well they will seal with your present deck and head surfaces, IDK. The surfaces are supposed to be pretty smooth for MLS gaskets.

With a .050" thick head gasket, your not gonna need much of an eyebrow to get to what you need. These pistons crowns are gonna be well over .300" thick, probably pushing .400" thick. This pix is all you are going to need for eyebrows in this case: Single Silvolite Coated Piston - 5.2L Chrysler/AMC/Jeep/Eagle (V8) 1967-84

No reason the reliefs have to be angled or much over .060-070" deep, based on what you have so far. Just find where the valve edges are hitting, make a pattern, and a light cut. Practice on an old piston.

Or a different cam. Can you share the cam PN OP? If you have an older style slow ramp cam, that is going to make this issue worse. It may be as simple as changing to a faster ramp cam.... which might be of benefit on other ways, depending on how you are using this engine/car.

And FWIW #2, the static CR here is not all that high....around 8.9 with an educated guess on the chambers.