I would tear it down and have it completey rebuilt IMO.
Otherwise, this thing is going to nickle and dime you to death to well over $2500 and when you are still having problems, you will be kicking yourself in the [censored].
Why don't you go see Pontiac Dude (Ken Keefer) in Brooksville? He is a great guy and straight up. He won't screw you and his reputation is excellent. One of the best builders of Pontiacs around.
What would I do? Depends on the servicability of whats existing and what you want to do. Unless racing the car, leave the heads/porting alone. A stock rebuild with quality parts (Comp Cams, Ferrea, TRW forged pistons) will do just fine. Maybe get new rods and have the rotating assembly balanced. $2500 is a drop in the bucket for a 400. A complete rebuild will vary greatly depending on what is needed. Costs can add up quickly.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
