| Plugs [message #301378] |
Wed, 01 June 2016 15:50  |
Dan Gibb
Messages: 24
Registered: May 2015
Location: Tucson, Arizona
Karma: 0
|
Junior Member |
|
|
What is the consensus for the best spark plugs and the model numbers, for the 455 with the HEI ignition?
The repair manual I have says, AC R 46SX. Any thing better now?
Dan Gibb
1977 Eleganza II
Tucson, Az
|
|
|
|
| Re: Plugs [message #301379 is a reply to message #301378] |
Wed, 01 June 2016 16:22  |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
|
Senior Member |
|
|
Dan Gibb wrote on Wed, 01 June 2016 13:50What is the consensus for the best spark plugs and the model numbers, for the 455 with the HEI ignition?
The repair manual I have says, AC R 46SX. Any thing better now?
Dan,
Right after I got my coach, I changed plugs to the recommended A/C plugs (AC Delco R46SZ, at the time). The next time I changed them, I put in some fancy Iridium plugs I got from Jim K. Probably serious overkill to install 100,000 mile spark plugs on an old engine. I didn't notice any difference in performance. Basically anything that makes a spark should do the trick (as long as it is the proper size plug for the engine) Just run them gapped at .060
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
|
|
|
|
| Re: [GMCnet] Plugs [message #301381 is a reply to message #301379] |
Wed, 01 June 2016 16:31 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
If you have GM HEI, do yourself a big favor and gap plugs at .045". Any
more than that and you will start replacing ignition coils and modules at
frequent intervals. Not just my personal opinion, but what they taught me
in GM training school. But, it is a free country, pay your money and take
your choice.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jun 1, 2016 2:22 PM, "Carl Stouffer" wrote:
> Dan Gibb wrote on Wed, 01 June 2016 13:50
>> What is the consensus for the best spark plugs and the model numbers,
> for the 455 with the HEI ignition?
>> The repair manual I have says, AC R 46SX. Any thing better now?
>
>
> Dan,
>
> Right after I got my coach, I changed plugs to the recommended A/C plugs
> (AC Delco R46SZ, at the time). The next time I changed them, I put in some
> fancy Iridium plugs I got from Jim K. Probably serious overkill to
> install 100,000 mile spark plugs on an old engine. I didn't notice any
> difference
> in performance. Basically anything that makes a spark should do the trick
> (as long as it is the proper size plug for the engine) Just run them
> gapped at .060
> --
> Carl Stouffer
> '75 ex Palm Beach
> Tucson, AZ.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
|
|
| Re: Plugs [message #301388 is a reply to message #301378] |
Wed, 01 June 2016 18:12 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
Can't go wrong with AC plugs in GM vehicles. And they are cheap. The downside to 100k plugs is you can dammage cyl head trying to remove them after so long. And that costs like a gross of AC plugs.
John Lebetski
Woodstock, IL
77 Eleganza II
|
|
|
|
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
