Well my calcs are pretty close and I think it looks like you might be well off to use the Mr. Gasket 1121G or the Mopar Perf version of that gasket.

I think your first Hughes cam choice, the 216whatever, is a really solid choice. If you have to have the rumpty idle then the Whiplash is for you. Otherwise the first cam is IMHO head and shoulders above any rumpty idle cam if you intend to actually drive it. Especially in a pickup.

My guess-top dyno says, properly tuned you're knocking on the 300hp door with well over 400 lb-ft of torque.

R.