CAM,CARB,EXHAUST,HEAD work very well on these not necessarily in that order.
Ask yourself what you want from car power wise, then you will know what spec to do it to, there is a good book by SPEEDPRO, how to power tune ford sohc engines.
I had a few pinto's, 2.1's work well using V6(cologne) pistons, had head by Roland Hayes(HT racing) who are masters of pinto, high torque cam, 32/36 carb in a auto sierra, was way faster than my friends 2L sierra manual injection, and good on the gas as well.
You need to know how much power you want before you know what is best to do.
tabetha