Hello guys,
Would you please tell me thew spark plug gap I should set my plugs to?
I've got a 1973 351C 4V with an HEI distributor (coil on cap - chevy style) Taylor 8mm Hi-Energy cables & Autolite AP25 plugs.

Thanks

 

i'd go .040"

 

every ford engine ive checked on nappas store on s plugs gaps says 0.040"....

 

Thanks a lot.
Won't the HEI dizzy make a difference? Or 0.40 is what you recommend considering the dizzy already?

 

it's a dependable gap, a little more than the common .035" for points, and with the HEI it should never miss a beat. of course you can always try .045" but make sure your plug is capable of that gap without bending the electrode at an angle to get it. there are different plugs specifically for wider gaps, the electrodes are longer and don't need to be mis-shaped.

extended tip plugs are usually designed for the wider HEI gaps.