DeadSkunk wrote: An early Falcon would be a good basis for a RWD Zetec and T5 combo, just to be different.
I like the 2.3L Turbo option as well, but for the lightest of the bunch a healthy zetec is a great option too.
Example: 2.3L Power http://www.build-threads.com/build-threads/4-cylinder-turbo-68-mustang/