Pulling engine and TH350. What to inspect?

[NaturalSnapple]

In about a month or so I plan on pulling the 350 and the TH350 from my 71 C10 to replace seals (both engine and transmission losing fluids). The engine is original but has been worked over by the PO - it has an aftermarket intake, carburetor, long tube headers, and the cam is very lumpy, but I have no details about the cam or even if it's still flat tappet.

With both out of the truck, what would you recommend for me to inspect/replace. Should I pull the heads and check the internals before changing the seals to make sure there isn't anything to be concerned about? I'll be pulling the intake to see what kind of lifters/cam it has, but I'm hesitant about pulling the cam itself.