I have a 305 in my 91 currently trying to find a new motor to put in their and re build. What is a good motor to build with a 350 under 2500$? Please give me some specs and how much HP TQ

 

Put a new GM 12496821 intake manifold on a new GM 12530283 Vortec 350. That'll eat all your budget, but should feel strong once the computer learns to pulse the injectors longer. Should happen in a few miles, but you may still have fuel starvation at times until you upgrade the injectors. Then your car will be ready for a new Holley 670-cfm TB which includes adequate injectors, plus the extra flow will support more power than your stock TB can flow. And headers / 3" cat-back and a 3.73:1 posi rear, and SFCs, as soon as you can afford them, unless you already have all of that done. Once you get all of that done, you might consider a 210/220 112 480/480 cam or something similar. If you already had the Z28 exhaust, you could expect around 260 HP right away, and end up around 300 HP. But if you still have stock LO3 manifolds and 2.25" exhaust, you'll be around 200 HP until you fix that. Still, it's worth doing the 350 first just for the torque.