No, not yet, I don't have time til this weekend, I am just looking for as much info as possible and I want to order performance parts! thats all, thanks for the advise.

Oh..in that case..

Get your $10,000 ready and just swap out the motor. Seriously..though.. check it out..you are taking the right steps by fixing the issues before trying to push it further.

It sounds alot like an intake lifter to me.
So is the car backfiring thru the intake manifold? You kind of hinted that it was ...

It sounds like it is, but I don't know for sure becasue the only other time I have heard that was on a 83 caddy with the diplacement on demand, the lobe on the cam wore out and wasn't opening one if the valve and it was backfiring thru the throttle body, but that is a totally different animal.

If you say its running on 5 cylinders, you can check the wires to make sure one is not shorting out. Do this in the dark and you'll see a fairly constant spark whenever the coil sends one to the spark plug.