315/50, 28". You're probably right on the gear. My 340 only picked up .04 going from 3.91 to 4.30's. The pick up was in 60' and carried it through the 1/8.
Found out the hard way. Most any small block, they like avoiding high gear in a three speed. 1 to 1 doesn't accelerate as quick.... lol...
My Little pooch motor i am running right now, had howling 4.10’s in it, swapped in 4.30’s thing hates getting put into high gear quicker... longer distance to cover
Want some 1/4 time slips buddy. Cool you are getting to leg her out