Palmsprings,
ScotiaFE pointed you in the right direction, need a little more info to help make it really run
- Which intake do you have now?
- Which "cross bolted" heads, I assume C8AE-H (can be seen near the two center spark plugs)
- Are you willing to run headers and aftermarket dual exhaust?
- What is the budget?
Odds are the heads are poor performing GT/unibody/truck heads, the intake is a Performer, and the car has manifolds, all of those things combined with a slow ignition advance curve makes the 390 cars very bland performers
Good thing is, a set of headers, alum heads, a good intake, matching cam, and a distributor recurve can turn a 390 into a very healthy engine, but it takes money
The good thing is, guys here can help you build mild to wild, focus on where you want to make power and be very honest about how you want to drive the car and we can steer you in the right direction