What rear shocks for 69 Mach?

I have some old adjustable Konis and just bought some Summit adjustable for drag racing. The Summit ones are too long in the back and are about bottomed out at ride height. It didn't even cross my mind that I would have a problem. The Konis are about 10 inches collapsed and the Summit ones are 12. My car is about 26 inches from the ground to the top of the wheel well opening with a 255/60/15. Isn't this about normal? I'm looking for more of a drag race shock but all (race or not) are too long. At this point all I want is one that fits and isn't super stiff and expensive.