I installed a 1991 GMC 3500 7.4 TBI system in a 1972 402 powered truck for a friend. it's a little rich at idle (open loop) figured it would be. but it lacks power and the 91 donor truck had a knock sensor in the block but no wire on the factory harness on B7. so we didn't install the knock sensor and WINALDL is reporting a ton of knock and fouling the timing advance. We installed an MSD older HEI and used the tach lead to fire the injectors and it ran great. We would love to have the advantages of closed loop operation. The 402 is completely stock accept for headers by the way. It has the small cap separate coil dizzy. No esc or wiring for it in dizzy.

Thanx in advance for any help!