Seen it done use the pulse wire for door latches lock feed and unlock feed respectively dont press fob twice or they will be out of sync. Dont know what wires or colours
Have you checked all the basics timing plug leads right order. R the plugs getting wet? How long has the engine being stood if no oil pressure and the lifters r empty the valves will not open fully.
Crash boxes good and strong. Brakes could go for a disc brake conversion or fit LWB backplates and shoes etc. Overdrive would help and a 5 bearing diesel lump. Could also fit a servo.
Voltmeter on battery at rest 12.2V check when cranking should not drop below 9V voltmeter -ve terminal to battery-ve and the other end to engine block should be no more than 0.5V. Let me know what u get.