Since I don't come here often and was asked to comment so here goes:
#1 under no circumstances use ANY overdrive without a blower or nitro. I've slowed down using our .96 OD on natural aspired gasoline.
#2 with your torque (both 270-302's use the same 4" stroke) a 3 or 4 speed works great and yes the Jack Kelly rear engine tank Lakester #664
used cables.
#3 not a necessity but we only use 3 gears of our Tex T-101 1.61, 1.20, & 1-1 You push off at both places you don't need a lower 1st or need to
use it.
#4 one of the fastest GMC powered Lakesters runs a turbo 400 with a truck converter and one of the fastest GMC coups uses a turbo 350. You
can push off and drop into gear it's like not using 1st in a manual. Circle track guys use them without a torque converter and a pedal to
move oil in the trans in the pits. I don't know how.
Yes I ran twice in high gear only 85% nitro the record was 202. I qualified at 205 and returned at 215 for an average of 210 and received a red hat.