Here is a "better late than never" response to both posts.
Trans go is one of the best shift improver kits you can go with. Talk to your local tranny rebuilder or speed shop to get prices. Probably less than fifty bucks for the kit.
Now for both of you, the Edelbrock Performer RPM is a great intake for even the mildest of Poncho's. Forget the 454 idea, you almost made me puke!!!!!!
A good Q-jet or a 750 vacuum secondary Holley (like the #3310) will be plenty. Some 1-3/4" headers, a 2-1/2" X-pipe, and either some Magnaflow or Dynomax Ultraflow mufflers will help a bunch and sound great without being obnoxious. There are lots of cams to choose from, but the intake and exhaust mods are plenty to get you started. Don't overlook the fuel system and distributor/ignition system. Much power can be uncovered with a proper "tune" and the parts you already have.
Jim Hand has a new book out on performance Pontiac engine building. You need to buy it, read it, roll up your shirt sleeves and start at it.
I havn't been looking at the board real regularly, but send me an e-mail or PM if you have more questions. I will try and keep up with this thread.