Using a fused power wire to the dimmer in & out to the orange originally circuit will restore the lights , factory gauges need a power wire to the volt regulator sending 5v to the gauges
My suggestion is the clutch not releasing fully , I have had a lot of problems with CF clutch clutches in the past .
If ti shifts fine off or moving that still makes sense , something is wrong with the clutch
Sounds like the wires are crossed at the trans switch , the two outer wires are power in & out for the reverse lights & the center is the ground for the start solinoid
You do not want to go lower than 180* , but tuning the carb precisly could help , it may be to rich when hot or a Coolcarb spacer to keep the carb temp down .
Often carb tuning , any carb has a Power Valve circuit but different ways to tune it , if the vacuum drops too low at idle in gear the powervalve will open & add fuel enrichening the fuel mix causing it to stall . You need to get a vacuum reading at idle in gear , the power valve needs to be 2"...
The EFI system makes a Huge difference , Multiport EFI doesn't care about fuel suspension in the air flow so A large throttle body & wide open intake works great as all you are moving is air .
A Throttle body injection is completely different the fuel is added into the air flow & travels...