neveridle

Hello, I recently purchased a 1968 Cutlass with the original 359 2 barrell that the previous owner installed a electronic ignition into. Can anyone tell me what spark plugs it should have in it? Thanks neveridle

70sgeek

you'll get many responses to that question, best just to search the forum for past threads - other option, use parts search from your favorite parts store website (Advance, Autozone, etc) for '75-up Olds 350 (they had the factory HEI by then).


just to get you rolling in responses, I use MSD p/n M4637384 Iridium spark plugs gapped at .035 in my '72 350 which has been upgraded with a Pertronix electronic distributor (i.e. HEI) coupled w/MSD blaster coil.

svnt442

I wouldn't use the factory plugs from the HEI years because they are designed for gaps of .080, and in my opinion that is just too wide. They were still experimenting with gaps at that time and that is just too much.
I'd just gap your factory plugs to .040 or .045 and be done with it. That should let things work quite well with the factory HEI.

neveridle

Thank you so much for the quick response! That is a excellent idea! Everyone on here is always so helpful. Thanks again, neveridle

oldcutlass

Is it a large cap HEI or a Pertronix type points replacement? Either way your stock plugs will work fine gapped @ .040 or .045 for the large cap.