If you find a good cross-flow(later style) radiator that's close to the same measurements as the space in your truck-(with radiator stood on end,of course) you should be able to have a radiator shop re-fit the neck and inlet/outlet to make it a down-flow to fit your truck. They'll probably clean it out good and pressure check it too,so it'll be ready to run. You might have to do some custom fitting on it as far as mounting holes etc. but that's no big deal.
Speed
