91 gt build

I would like to know the answers also going wit ha similar set up for my car

That will wake the car up a bit, 4.10s will be great. Theres nothing there that hasnt been done 10,000 times so you're not really going to hit anything unexpected. Go for it

If your pulling apart the manifold just replace the heads. If there is non smog emissions go with a decently radical cam to go with heads and gears. Best upgrade ever. You won't regret it except your wallet might if gas prices eclipse $5 per gallon

If you haven't bought any parts yet don't. Do yourself a favor and get an explorer top end. It has the same heads/intake as a cobra and it comes with a 65mm tb. Use your 19lb injectors and get a 94-95gt maf. Unless you already have the e cam laying around don't waste your time. The stock cam is a great piece, but if you want a good budget oriented ots cam the tfs1 is at the top of the list. Either way you have no business replacing the cam if you haven't upgraded the heads yet. The combo I just listed I have personally pieced together for less than 500 dollars and will give a solid 30-40hp more than what you have listed.

I agree with stkthyn, don't bother with the cam if you keep stock heads.. It will sound better but there will most likely be minimal to no gain. Explorer top end is a good budget upgrade, and still has good street manners.