Another aluminum radiator question.....

I been looking around the forum to try to get the answer But im not having any luck. I am planning on buying a aluminum radiator for my 75 duster with mildly built 340. I am also using a BeCool puller electric fan. Not that I'm trying to skimp on parts but I can't really see paying the $750 for a direct fit unit. The guy at my local speed shop says he can get me a nice BeCool universal unit for half the price and tig weld the tabs on the radiator for me. I tend to overthink things so here is my question! Is there any advantages/disadvantages with replacing a downflow radiator with a Crossflow one? Also would welding directly to the radiator be a good idea? Any help would be greatly appreciated!