Hipo65, the only way you can still use your SBP wheels on an 8 1/4, would be to redrill the axles and drums, but im not even sure that would work as I have never tried it or know anyone who has.
they are considerably stronger that an open 7 1/4 but for your engine combo you might want something stronger. I would try to find an 8 1/4 or 8 3/4 for it. your 7 1/4 should live till you find one. you can probably sell the smaller SG and recover much of the cost of a bigger rear.
i know that when i put the rear seat from a 74 dart 4dr into my 71 valiant 4dr, the mounting tabs were in a different location. i ended up tieing them down with some heavy wire. i dont know if its a year thing, or a dodge plymouth thing
found out the 997 springs are a 4 leaf design, interesting because the car is a v8 car. my slanted 71 valiant has 6 leafs. also the 997 springs have a step down in thickness in the center of each leaf. anyone seen these before?
on the build sheet i found in my 66 dart, the rear springs are coded 997, both sides. are these HD or standard fare for a v8 car? the front torsion bars are normal v8 890,891 bars. also pinion is listed as 31. what ratio is this?
i keep looking at this 66 hardtop with a wasted front end. i am told it was hit by a firetruck. somebody took a torch to it and cut the front frame and sheet metal off. i was planning on parting it out but from the firewall back it has perfect sheet metal, no rust at all. my friend here in vegas...