I don't think you'll find a 4v intake or any speed equipment for a 3.8 V6. I looked in my Summit catalog and they had parts for a 4.3 but nothing for the small 6 that you got. Rebuilding your carb might help but if the 23 year old engine is tired it won't make much difference.
The 3.8 never had much power when new. You should be looking for a 350 V8 to put in it if you want to burn rubber. Some of the third gen Firebirds came with V8 engines so It shouldn't be a difficult swap. If you can change the trans and rear end you should be able to do the swap with a little help from your new friends here at CHR.