Hi guys,

I currently have a 9lb non-intercooled S-trim setup, and want to spray a 75 shot on top of that for a little cooling . I will probably be pullying up to 12lbs in the near future

My motor is a 8.5:1 fully forged 383 with 50lb injectors.

Should I run NGK tr6's, autolite 103s, or a colder plug? Also what should I gap them to?

Thanks for the help folks!

 

Plugs for a blown 383 with Nitrous, .....

 

Run a very cold plug, much colder than a TR6 or Autolite 103. I am running an NGK with an "11"00 heat range, which is 5-6 heat ranges colder than a stock plug. The center electrode is basically flush with the plug flange. They are gapped at 0.035" and I have had no fouling problems with a Crane box and Accell coil, stock wires. The plug pn won't help 'cause they are for AFR heads.

Rich Krause

 

Well I have AFR 220s.... hand over that pn! hehe.

So what are the options that aren't quite as cold as your NGKs, yet colder then Autolite 103s and NGK TR6s? I know you are setup for 750-800'ish rwhp - I am looking more into the 550-600 rwhp range on 94 octane so I do not think a 11 heat range plug would be optimal...

Thanks again!

 

If I remember right, it's a BPR11ES. They make the correct plug (14mm, 3/4", non-tapered seat) in a number of different heat ranges. As I said, I don't see any fouling so there's no reason not to stick to a very cold plug.

Rich Krause

 

Isn't the normal LT1 plug a .708 reach? Do the AFR's take a slightly longer plug, or do the extra 40thou not really make a difference?


thanks,
Chris

 

AFR recommends a 3/4" reach plug. If the heads have been milled, a shorter plug might be in order.

Rich Krause