All the ford versions Ive ever seen were 6.69. There may be some different ratios with the chevy or dodge version, but I've never messed with those. If the trans you're looking at has a high 1st, its prolly a T19. They were used in the Ford chassis (and a few chevys too). The diesel T19 has a 4:1 1st. The t19 will have a cast iron top cover, the 435's is aluminum.