Ok guys I'm about to install my new gm style hei in my 1970 455 toronado...This car has gasketed spark plugs while the tapered version started with the hei in 1975. Whats the best gasketed plug to use at what gap?...thanks now, cliff

 

i think Oldsmobile used the same washer type plug on the newer heads also. i know that when i went to HEI on my rallye i used plugs and wires for a 77 cutlass and had no trouble. i am now going back to the original distributor.

 

hi Eric, I don't think so, I used to work as a wrench in 75 and I remeber clearly all gm cars changed all engine tune up parts to the new lead free requirements, we thought it all sucked and that would be the end of the good performace cars....and it was for at least another decade when they finally started to consider performance again, I remeber doing a tune up on a new 77 firebird t/a 400 four speed (gorgeous car)and thought this car should be fairly quick, then when I test drove it I had to laugh...and another time challanging a guy in a new 84 vette with my 67 caddy sedan deville knowing I'd trounce him and he backed down...how humiliating that must've been for him...thanks for imput tho, hey you still got that blue toro?...I need interior rearveiw mirror...thanks, cliff

 

Nope. Olds used gasketed spark plugs. The 80 I had with a 260 still had them. My 76 Salon with a 350 had them as did my 75 engine.

 

I'd use an AC R43s or R44S (44's are hard to get nowadays) or the equivalent of your favorite brand and gap them at .045". Opinions will vary on this one though.

 

well It must be early senility then......but keep the opinions comm'in boys! thanks!

 

gap anywhere from .045 to .055 depending on if your coil is stock or upgraded.

 

Lead content of the fuel has nothing to do with any part of the ignition system.

I always use the same plugs and gaps, for that engine. The plugs don't care how the spark is made.

Norm

 

I'd use AC R45S or R46SX gapped at around .045-.050. You go much wider than that, the HEI will spark it, but that's a lot of gap to jump. Believe it or not an equivalent set of Motorcraft or Autolites will work well too. Then there's NGK which, in spite of their Japaneseness, I think are the finest spark plugs made.

My experience is that Oldsmobile engines don't really like platinum plugs. Or mne don't anyway.

 

I also use AC Delco R45S spark plugs.

 

i would agree with that but i just can't bring myself to put them in my American made Oldsmobile's. i just use them in my Honda 3 and 4 wheelers.

 

Ive put HEIs in my 74 Cutlass 350, a 66 Pontiac Tempest sw with a 74 455 (with 69 428 heads), and a friend of mines' 70 GTO with the original 400, and used the stock AC plugs for whatever the application called for on the heads that were used. All 3 have been in ther since the late 80s/early 90s without problems. Just install your factory plugs then open up the gap to about .045 and you should be fine. It is the heat range you are after as well as getting the plug to seal right in the head. HEI just fires the plugs better across a wider gap.

 

i run R43s's gapped @ .050"


bill