Originally Posted by lonerangerusa
Help needed is I installed a 4.3 plus trans into a67 ford econoline. The 1989 astro had a FAL C 187 1 rear end with 205/75 r 15 tires (it should be a 3.42 rearend according to my Info.)1967 Econoline has a WCR-S1 3.00 6KA 783 rearend. I will run tires the outer Dia. same as the 205/75 R15 with the Ford rearend should I regear if so to what ??? I do want to keep performance & fuel economy as it was or as close as possible Thank's Loneranger
I would run it like it is with the Ford 3.00 rear, see how you like the power before you change rear end ratios, then adjust the speedometer gear to make the speedo read right. Speedo gears are only about $ 10 or less.
If not, Ford makes a 3.25, 3.40, 3.50, 3.56 ratios that could be had at a yard.