I did a 3'' relocation on an original 69 swinger 340, installed a small block stroker with a 4.10 8 3/4, 315 tire and run pretty consistent 11.0's. I did an offset shackle kit on a 68 valiant big block stroker with a 4.10 8 3/4 275 tire and run 10.80's. The 3''kit was alot of work, and would be tough to return to original IF ever desired. Ive done both.
