Len, my V-8 springs measure .615 wire diameter and 14 1/2" out of car height.
My car is a 1980, so these springs were out of a junkyard V-8 with A/C Monza. I had them put in shortly after buying car in 1990 as it was just too low, wish I had saved the old ones now that the much lighter LS-1 is going in. Speaking of that, I had the LS-1 sitting in car with the turnbuckles holding it in place, putting jack under control arm would not compress springs, just lifted whole thing up. The front bumper, nose, hood, radiator and steering apparatus were not on car, so that may have been enough weight to effect it considerably.
1980 Monza, 305/Th350 removed for LS1/T-56 swap, can't wait to My Project