I have a 425 Toronado in my '66 442. I believe the engine has a W30 cam in it. My car is a 4 speed.

I am putting a Pertronix Ignitor in the stock distributor and am also installing a Pertronix Flame Thrower 1.5 ohm coil.

I am going to use Delco R43S spark plugs.

Could someone tell me what gap I should use in the plugs?

Thanks
Pat

 

There's no set guideline here, and I do not know whether your coil has a significantly greater output voltage than the stock coil does, but I would say that the stock 0.035" is probably your best bet.

If that coil has a significantly higher output than original (disregarding hype), you might go up to 0.045".

- Eric

 

You may have to experiment a little. I have an HEI on my '69 400-G and have found that 0.045 works pretty well. I don't know how hot the spark you'll get from your Pertronix combo will be, so at a guess I'll suggest starting with 0.040. A mitigating factor may be those AC R43S plugs which are pretty cold and could be expected to foul with a stock ignition.

 

Thanks for your advice.

Pat

 

How can you tell if the plug gap is too large?

 

Car runs bad.

- Eric

 

Smoke comes out of the coil...