Your set up could go into the 11's if it were matched right. If i were you I'd spend the money for a higher stall. Its not going to hurt you to run a 3200 stall on the streets.

My friend and i have a 83 monte carlos, both of use built them almost identical (not on purpose) and he is running 11.8's with his and i'm going to be into mid 10's on juice with mine.

He's running a torco converter that proved to be really worth the 450 bucks instead of a tci that costs 725. He's running a hydrualic 503/510 lift comp extreme energy cam, 10.3:1 compresion, 215cc iron eagles, 355 ci, 850 double pumper and a dual plane intake. The car weighs 3450 with him in it so its fairly light. For your application, i'd say get the 490 lift cam (i had that in my car last year) or the bigger 501/510, a higher lift converter, 3200 with the smaller cam and bigger with the bigger cam, get the heads ported, and if you have piston to valve room get them milled some to bump up the compression. just my .02