I really like your car. I am also building a '38 Pontiac. It's a Silverstreak Six 2 door slant back sedan. It will have a period correct 1960 389 Tripower S.D. with long branch headers, TH400, '78 T.A. rear end with 3.42:1 posi, and Heidts front end.
I have the engine, which runs well but needs re-build and exhaust manifold, floor shift trans, drive shaft, rear end, front and rear springs, front suspension parts, drums, spindles, wheels, master cylinder, and various other parts.
Email or P.M. me if interested.