lt1 383 ?s
IMO if your looking for a fun car to drive just rebuild the stock motor maybe do a cam swap with bolt ons. I loved diving mine an sometimes regret goin to path I did, but I know it will all be worth it to start it up an hear this.....
http://www.youtube.com/watch?v=CHF80...e_gdata_player
Expect to spend 5-6K minimum and several months. If you want a quicker, cheaper way to hit 11's just get a baby cam and some good ported heads....done. It's even possible to hit mid 11's with JUST a baby cam and bolt ons with the right tire/suspension/stall. 

