Your truck all ready has a nine inch rear, you can tuck some pretty large tires in between the rails of a uni buy paing attention to the backspace. Typically you 9" will have a 3.90 ratio if behind a six and 3.50s behind a eight.

I currently have a 63 Pro Street Uni under the knife that when complete will have a 428FE with dual carbs and a C6.

The trucks is mini tubbed and has a full aluminum bed.

Narrowed 9" 46" hub to hub with Moser custom race axles running 31x18.50x15 Hooiser Pro Street Radials.

The truck is set up for a 3" ride height and will decapitate snails.

A fast truck will need lots of modifications to bring it up to snuff. Brake upgrades will be the most important. Unless you want the gasser look which is currently growing in momentum (Street Gasser) a new front suspension is in order, of either a MII, Volare, Dakota, Aerostar or LTD. As a fast truck will not like a stock straight axle in stock trim.

As for a motor. anything but a belly button GM! There are mounts made to just about bolt any motor made by ford into the Uni via a custom crossmember or adapted to a suspension crossmember with custom plate mounts.

I reccomend a new 6.0 cammer. at 14K it wont break the budget..LOL, its all relative. speed cost money son how fast do you want to go.

Garbz