[Caddylackn]

I would like to see this with a 455/T400 swap. A buick long tail T400 would enable you to swap in a one piece driveline from a later model square body.

I would rebuild the stock Quadrajet from the 455 to a Stage 1.5 or Stage 2. Get Cliff Ruggles book on Q-jets. This would give you the best all around driveability, performance, and mileage for street. Use a later model quadrajet float setup that gives you more fuel capacity in the bowl. Run a new 3/8" or 7/16" fuel line, and I would add a return fuel line off the mechanical fuel pump to prevent vapor lock in hot weather from a Big Block and headers. Can you convert to BBC truck headers to fit on the 455 heads by switching the header flanges?

With a 455, column shift would be fine, but make sure you have a working kick down switch. No need to do a lot of shifting up or down with a big block torque monster. If you had 3.08s the mileage would probably be better than a stock 350. If you have 4.11s then I would swap those out to 3.08 to take advantage of the lower stronger torque curve.

You don't need a high hump tunnel for the T400, mine came stock with a low hump tunnel and a T400. You might need a high hump tunnel to use a T400 floor shift though.