I made a switch that looks like a trigger on the pistol grip.
Racing I shift from first to second, then second overdrive and then third overdrive.

8093405-IMG_2295_s.jpg (96 downloads)
1970 Road Runner 505 cid MCH CNC ported Stealth heads MP 528 camshaft 4 speed GV overdrive 11.98 @ 117 on street treads