If you want to be different, put a GMC Big Block v6 in them, or maybe a flathead ford, or a ohv inline six (pontiac), or straight 8, or a v12 ford, or a v16 ford, or a v12 GMC or a 3-71 or 4-71 gmc diesel, or a perkins diesel, A nailhead 322 buick is a good engine also. There are adapters for everything now, not like the old days. I saw a guy that put an allison trans behind a flathead......the sky is the limit.

Jay leno has a roadster with a 800cu tank engine.

64 & 66 GMC long fleetside 4x4
Cartwright, OK