I'm gonna go out on a limb here...but... 7MGTE? Either that or a 22R or comparable Toyota motor. Keeping it carb'd will ensure an easier install, but if you are planning on doing EFI anyway with a standalone, you might as well do something unique. Shit, you could throw all the ford guys a curveball and put in a 13B or something, hehe.
Actually, now that I think of it, non-turbo 2JZ-GE's are wicked cheap and pretty much found everywhere.