Hi,
New to this site.
I posted on the Forced Induction board also.

I have done a search but have not found an answer.

I have a 2001 4X4 Suburban with a 5.3 and a Magnacharger (the first system
that dosen't have a Intercooler).

Here's the Question:
What Spark plugs should I run, I still have the Factory AC 41-985 plugs.
I would like to run 2 steps cooler but I can't find a plug # for the
AC Iridiums 41-900 series plugs that is two steps cooler.

As I understand the new numbering system used by ac delco has nothing
to do with heat range of the plugs.

Magnacharger just said to use the stock plugs, I would rather find a two
step cooler plug, I have a little spark knock going on.

Thanks for the help in advance.

 

I had the same exact kit. I ran NGK TR55's and they worked great. Gapped them at .35

 

You beat me too it!

 

I bet that doesn't happen every day.

I would leave this blower at the stock boost 5.5lbs if I remember right. Unless you plan on getting LS1 edit and put a very good tune to it. Or just run a little paint thinner in your gas if you go to the track.

You will get KR anything over 7lbs on 80 and above days that is for sure and if you don't belive me on this look at these picts. 91 octane gas + 85 degree day + outrunning Lightening on the interstate = a broken #7 piston.

 

Yikes!

 

hahahah

 

Ya I thought it was pretty funny too

It will be running this weekend before with more hp NA than I had FI

 

SAAWEET! What C/R did you end up with?

 

11-1 So no boost for me!!!

Project boosted/forged 427 is already underway though have lots of parts so far.... just reasearching and saving!! won't be going in my truck though, have another project that is 2wd.