88redconvert

Does anyone have the current part number for AC plugs in a 1999?
Thanks

Fed Up

ACDelco Part Number 41-985

I went with the NGK IZTR5B11, which is an OEM replacement, but some say built better than the ACDs. About $10 each.

racebum

41-985 has been discontinued, new number is 41-110

in my opinion it really doesn't matter if you use a 41-110, denso 5090 or ngk iridium.

all are top notch plugs, the delco plugs also use an identical looking, and possibly the same electrode as denso...which makes you wonder since denso was the OE plug in the z06

best value plug is the denso 5090 which are a hair under $5 each on rock auto. vatozone also does rebates on ac delco often at $2 a plug bringing them down to $5 a plug as well

Fed Up

True, although sets of 8 of the 41-985s are still available all over for cheap bucks ($30 to $40 on the 'bay for example).


I like my NGKs- what's your opinion on the new .40 gap they're shipped with? Would you consider bumping them up to .55 or so?


Thanks

racebum

no way. 40 is great, much less potential for detonation.

.55 would work on e85 or a mild race gas but it's just too dicey on pump and worth at most 3-5hp

some of the plugs, older ones mainly, were gapped at .44 which as large as i would go on pump

jlaw1313@comcast.net

I've run NGK TR-55 for two years and recently started to experience some detonation on pump gas. They are gapped at .55. Did not know any better. Thanks for the info.

laurent_zo6

Same here.