The dreaded "replaced everything but still won't start". It is true there is no drop-in HEI for these motors.
They use a bypass resistive ignition system as do most 12V points motors of the day.
I will have about 5-10 questions when you are ready. Test the battery or get a new one pretty quick.
Take off the camper and take off the spare from front before I go nuts . Hopefully they kept the tailgate. Keep the mirrors, they can be worth money. This is a really good truck with a good motor. Long lasting, powerful motor. I like them for a daily driver truck. But the motor is a boat anchor. I say that with all respect to GMC engineers. The motor is a design masterpiece. Except it's maxed out at 3800 RPM. Approaching 900 lb weight without trans. 60-66 GMC's are fairly rare, especially if it has factory options. Yours seems to be a non deluxe variety. That's OK. The originality of your truck makes it very valuable to some folks, so keep that in mind with all your changes. The GMC crowd is very loyal. 1966 is a premium year. Last year for that body style.
Pertronix is OK. Not necessary, but OK. The newer II and III are better than the old Ignitor I. THE "POWER RELAY" IS A 100% SCAM. If it works, it means you did not install the Pertronix correctly in the first place.
Last edited by bartamos; 02/27/20216:09 AM.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
. Hopefully they kept the tailgate. Keep the mirrors, they can be worth money. This is a really good truck with a good motor. Long lasting, powerful motor. I like them for a daily driver truck. But the motor is a boat anchor. I say that with all respect to GMC engineers. The motor is a design masterpiece. Except it's maxed out at 3800 RPM. Approaching 900 lb weight without trans.