Hi, we have a 2007 Winn with a gas 8.1L Vortec engine. I want to replace the spark plugs and wires. According to the manual I am to use AC Delco 41-983 plugs. Yet when I check NAPA, Advance and O'Reilly's, all 3 claim these do not fit and list others. Yet all 3 do carry them. Worse, one store lists one the fits that the other says does not, and vice versa.Further, I check the Workhorse parts site, they say should be AC 41-101, yet none of the stores say that, yet do carry them. What a mess...Should I heed the manual says and ignore the store fit claims?Should I heed the Workhorse site even though the stores disagree, and does not match the manual?Or should I heed the store's advice? Even then not sure how to pick which one? Plus do I use the gap out of the box or adjust?Any inputs would be appreciated, maybe they do this so we won't try to change them ourselves, argh... :h

Try looking on Rockauto.comLook under 3500 pick up 8.1AutozoneWhat Workhorse chassis do you have?

I would trust NAPA but not he other stores.However, I'd go by the GM manual before I listened to anyone in a store.The gap should be listed under the hood or somewhere in the vehicle or the manual. I wouldn't just assume the gap was right out of the box.

Quick question: what plugs are in it now?

I had the 8.1 years ago. I replaced the wires with Taylor and the plugs with AC Delco 41-101 Iridium spark plugs, gapped at .45, not .60.

I trust my own searching before my local NAPA store. They barely have a computer system.Napaonline.com maybe a better place to check.

Spark Plug Confusion ?? | Good Sam Community

enblethen
Nomad
Feb 19, 2021
Try looking on Rockauto.com
Look under 3500 pick up 8.1
Autozone
What Workhorse chassis do you have?
KD4UPL
Explorer
Feb 19, 2021
I would trust NAPA but not he other stores.
However, I'd go by the GM manual before I listened to anyone in a store.
The gap should be listed under the hood or somewhere in the vehicle or the manual. I wouldn't just assume the gap was right out of the box.
wildtoad
Explorer II
Feb 19, 2021
Quick question: what plugs are in it now?
Rocky2
Explorer
Feb 19, 2021
I had the 8.1 years ago. I replaced the wires with Taylor and the plugs with AC Delco 41-101 Iridium spark plugs, gapped at .45, not .60.
enblethen
Nomad
Feb 19, 2021
I trust my own searching before my local NAPA store. They barely have a computer system.
Napaonline.com maybe a better place to check.
ernie1
Explorer
Feb 19, 2021
Uhhhh why not call your local Chevrolet dealer?
enblethen
Nomad
Feb 19, 2021
What Workhorse chassis makes a little difference. Some have 7.4 and others 8.1.
Bruce_Brown
Moderator
Feb 19, 2021
KD4UPL wrote:
I would trust NAPA but not he other stores.
However, I'd go by the GM manual before I listened to anyone in a store.
The gap should be listed under the hood or somewhere in the vehicle or the manual. I wouldn't just assume the gap was right out of the box.

I wouldn't trust our local NAPA with a bottle of windshield washer fluid. Our local Autozone is excellent.

Honestly, I trust myself the most.
chuckftboy
Explorer
Feb 20, 2021
Generally there several plugs that will probably work fine for the same engine but if it were my coach, I would pull 1 plug and shop for that same number plug and eliminate any guess work
wildtoad
Explorer II
Feb 20, 2021
chuckftboy wrote:
Generally there several plugs that will probably work fine for the same engine but if it were my coach, I would pull 1 plug and shop for that same number plug and eliminate any guess work

What a concept! :S