340 Swap

Pull a valve cover and put a dial indicator on the push rod. That will tell you lift and duration.

Pull a spark plug out and get a scope from Harbor Freight to look at the pistons. While your at it pull all the plugs and put marvel mystery oil in the cylinders so you don't fire it dry.

Also turn the motor with no plugs with a starter to get oil on all the bearings. Or just prime the pump with a drill turning the motor by hand to oil both sides.