i have only one experience with a vintage air unit on my best friends 55 chevy. everything fit good with only minor bracketry fabbing by us, and it cooled very well ! it also tied into his original dash controls, which was a nice touch. since then, both of us has used a couple of ac only "universal" type kits, and for the [our] applications, those worked well also. we just had to use our "thinking cap" a tad more to position the evaporator inside in the best place possible. at the present time, we are installing an underdash unit from the 60's [that is in excellent condition, stored for many, many years] in a 64 ford galaxy 500. this unit was used for a varity of reasons. one, he had it, and two, it fits with the 60's style build of the car. it is being coupled with a modern sanyo compressor [twin V belt drive], aluminum crossflow radiator and condensor, r134, and twin semi-staggered electric fans. we both believe the system will work as planned. for my humpback build [which also has a cage plus engine setback which makes behind dash space tight, if non existent], i plan on using a divorced heat/cool setup behind the seats placed in wells in front of the rear tires, [heat in one, ac evaporator in the other] with duct work running either up the door jambs, or in the tunnel area forward covered by a console. still in the planning stage, so i know sort of what you are forced with as for space limitations. if the vintage air unit fits what you need and want, i am pretty sure you will like it. don't know if this has been helpful to you or not.