earlymustang

The manual specifies
BF-42 .032-.036 (std. 289)
BF-32 .028-.032 (hipo 289)

I could only find BF-45's (Autolite)

The car is not factory stock now either.

I am using Pertronix, Std. Dist./Cap, Repro yellow top coil, Upgraded plug wires (All Black ), Performer Cam, Peformer Intake, headers, Edel 600cfm , electronic v. regulator, new factory style solenoid (I know I know....not all of these components probably make a difference but wasn't sure).

Anyway, stick w/factory settings or use something different?

Thanks

Derf00

BF 45 is a hotter plug meaning it transfers heat to the block at a slower rate. That would be helpful if you were running points and condensor but with an electronic spark, you may get some detonation (pinging). Try to find a colder plug or retard your timing so you don't ping. Retarding your timing will hurt performance though.

Soaring

The pertronix, in combination with their flame thrower coil will allow you to open the plug gap to as much as 0.045 or so. However, there are quite a few guys that I know that don't change the factory settings even with that combination and like it. I have the pertronix and flame thrower coil on mine, and I am running 0.040 plug gap setting and it responds really strong. I am not sure about the yellow top coil. But, at any rate, just putting on the pertronix module will not warrant changing your factory plug gap with those 45's. Just for grins, gap them to 0.038 and see how it responds.

earlymustang

I have actually noticed some pinging. What type of plug would you recommend?

67coupe

If you have to resort to getting a performance plug like Accel to get the colder ranges. Like soaring said .040 is a good compromise. The wider gaps give you a hotter spark and add some to low end power, but they tend to take away on the top end if you get to wide.

19stang66

I just bought Autolite 45's the other day and gapped them to .034. I have a 289 bored .030 with a converted pertronix ignitor ignition and a performer intake, holley carb and tri-ys. Otherwise my engine is stock. Is that a good plug and gap for my setup? Not meaning to hijack.

Soaring

Yeah, unless you also use the flame thrower coil in combination with the pertronix module, you will need to stick with the 0.034 gap.

19stang66

thanks soaring