Ok, I had a 2 door Dodge Shadow ES with a 2.5 NA and a A-520 5 speed, 3.55:1 gears. Stock it was a slug. Weighed about 2900 Lbs. But I did a few mods to it. Got Hypereutic pistons that bumped it to 9.5 and then shaved the block 0.030 and 0.020 off the head. The measured CR was 11.2:1. I then ported the head and put the middle sized valves in. Ported Iron ex manifold. Then 2.5" pipes. I had a LRE 260 Degree Roller cam. Removed the balence shafts. Deep oil pan with a windage tray. Mallory VI version of a MSD multy-spark. Weber 2v 32mm carb. Weight reduced down to 2500 LBs. It ran 14.25's if I short shifted at 4500 RPM. Got 41 MPG, 90% freeway, if I tried but normal driving it avaraged 37 MPG in mixed traffic. My 65 Cuda weiged at 2900 Lbs with a TEEN, A904 and 7 1/4 rear.

On a 3.9 V6, find a 3.8 Buick Type T turbo setup and swap in on. With 4 to 6 PSI should work. I just happen to have a Type T setup for a Q-Jet 4 bbl.

Put a 2.8 CRD from a Liberty in a A body... There are loads of hop-ups for this Deisel. Stroke it to a 3.1, bigger turbo....... Stock was 160 to 180 HP with lots of torque.