New to site with 360 question

You could use a shorter tire, and a looser converter as you need more stall when the car is light. The engine is down on power if you car is actually 2200 lbs. I would take the engine apart and find out whats going on inside, as the engine is only producing about 250 hp to the ground. We have a 318 thats in a car 400 lbs. heavier than yours and is a tenth faster, so there has to be something wrong with the engine and because it's a 360 it should be a good bit faster than us. I think that a good disassembly and re-machining of all parts is where you need to go now, as something is amiss.