spark plug ???

['67 Belvy II]

I have a bone stock 383 2 barrel and I'm not sure which spark plug to go with. she's a cruiser and I don't hot rod her "much". I don't know weather to go with a cool or hotter plug and the geniuses at the parts store can't even tell me which is the hotter or cooler plug, the autolight 85 or 86. I appreciate your input guys. Thanks. Anthony NV

 

[tpodwdog]

86 is the hotter plug...........i think

 

[lewtot184]

autolite 85 or champion j12y would work fine.

 

[Dennis H]

NGK's.

 

[WileE]

"genius at the parts store".... these days, that's an oxymoron.

 

[Funship32]

Well I will share with you what I know and what I suspect. With what I know- 85 is cooler than 86. Now for what I 'suspect': The 85's were used on many mopar engines- 383, 400, 440's (and on 2 barrel engines in '66) where as the 86's seems to be used ONLY on the 2 barrel cars, and other than the '67 318, ONLY on the 383's. I can only think that the reason for such was the 'idea' that 2 bbl cars were driven easier than their 4 bbl counterpart, plus single exhaust opposed to dual, and I seem to recall the C/R was lower on the 2 bbl engines (9.2 vs. 10) but don't quote me on that one. So..what to do? Run the 85's. In theory you can run a colder plug which may allow you to bump up your timing a tad bit and give you a bit more 'umph'! You only really need a hotter plug if you have plugs that foul out due to oil fouling (which my Chevy does 'cause it has worn valve stem seals). In theory the hotter plug will burn off the deposits which in a good running engine shouldn't be much of an issue.

 

[kidmopar]

bosch platinum the plug number is wr9fp