I used to run 5.38's and a 40 pound flywheel back in 68/69 in my 68 Z. I ran 12.50's @ 117 in the 1/4. RPM was crazy. That was good for about a 8.10 in the 1/8. Tires are a lot better today too. 5.38's caught a lot of people off guard on the street too !!
