Going into 5th with only 4 gears

Decided to change gears a bit.

A neighbour decided to sell his 1930 model A 5 window coupe body that had been chopped 3 inches already.
I have always had dreams of doing a hot rod.
So I dragged this homeIMG_3036 (1).JPG IMG_3037 (1).JPG
Plans are to build a chassis
Channel the body 4 inches.
Use my spare a833 overdrive trans
8 3/4 axle then I can swap pots with my dart.
Front i beam axle dropped 4 inches.
Have not decided on engine yet.
I sold my 354 hemis and have been kicking myself ever since. :-(
Would like to keep it pre 1960 style.

Choices for engines could be flathead, nailhead or stick with a stock mopar 340
If a good deal on an early hemi came up I may swing that way.
I am switching gears since My dart should be done this summer. Spare parts need to go to make way for the model A
What engine would you go?