I'd like to see some compression numbers. Also what your timing is set at. I've been fighting my dad's 32/36 for the last week due to it not idling at all. Very strange.

Random shutdowns really sounds like grounding issues. You'd be surprised the effects of bad grounds.

When you say the heater turns off you mean that fan stops right? or do you mean that it starts running cold? No carb problem will cause your heater to stop working.

1986 Toyota 4x4 22wEBer
Ported EB Offroad H/O Head "Josh Cam"
Ported Intake & Weber38mm Carb
LCE Header & 2.25in Exhaust
RB 1" BL, RS5000, SAW Tbars

2011 FJ Cruiser - SOLD