Which Shorty Plugs for Dart Pro1 Alum. SBC heads

[NapaZ28]

I need a recomendation on some short plugs that will fit my Pro 1 heads with headers. They are the DRT-11311112P angle plug heads and I have one plug that the boot is hitting a header tube. The plugs that I have in the motor now are Autolite AR 3923's.

I talked to my local speed shop and he said Accel doesnt make a plug with a .750 throw that will work in these alum. heads. Is he right? Also a recomendation on correct heat range would help too.

Thanks!

[Awesome Bill]

That is the shortest real race plug you should use, it is for a high compression engine. What compression do you have? Accell makes some real shortys but they tend to keep a ton of heat in them and can cause detonation. It is much better to dimple the header in that area. An AR3935 would be for a lower compression engine like 10-12:1 with decent gas, AR3934 could go to 14:1 with proper gas, AR3933 can easily go from 13:1 to 15:1 with proper gas etc. etc.

[lun40119]

I think that the Accel #s are 414s and 416s. I have a set of the 414s but...............what Bill said. Good Luck hope this helps.

Jake

[NapaZ28]

Thanks guys,

The plugs that came in the motor from the builder are Autolite 3932s. The motor is a 383 SBC with an estimated CR of 10-10.5.

I saw the 414S & 416S's on Jegs website but before I throw a plug in there that might cause some problems I thought I'd aslk for some feedback.

So I run the same heat range plug would you recommend the 414 or 416?

Thanks

[lun40119]

I ran the warmer accel taper seat with an iron set of heads on this same engine. You could probably run the warmer plug with no problems. With these aluminum heads I switchwed to the Autolites. I am running the AR 3924, and am trying the AR 3925's. One of the big reasons is that on the plug it says MADE IN USA. The accel says something different on it. Like in the other spark plug thread, it probably doesn't matter what plug you run, just make sure your gaps are right. If Bill says that plug holds heat, he is probably right. Good Luck.

Jake

[Awesome Bill]

I would not run the 32 plug in nothing but nos engines, turbo engines with 30lbs of boost and really high compression engines. That plug is stone cold. The AR3935 is what you should run with that compression. You can't hurt them. I ran out of plugs at the track one day with my race car and all I had was AR3935's I installed them and still used the 275 hp Nitrous and it run great. So if my car @ 15-1 with good fuel can run a 35 plug, you engine will do fine with it.