Ordered these and put them in my 65 442.

NGK 7355 Iridium IX Spark Plug

I know it’sa but after the fact since I already installed them, are there any issues running them?

i think I’m getting a ping while accelerating. Engine is stock minus ebrock intake and ebrock 750 cfm carb. Timing is set to 10 degrees, all in at 35 degrees at 2800 rpm running 93 octane.

any ideas? Increase timing? Retard timing?

 

If there is pinging, the timing needs to be decreased.

 

If I’m already at 10 degrees, how much more can I realistically retard the timing before looking to see if it’s another issue?

 

Did it ping before? Other than plugs any other parts changed or tuning adjustments? What is the engine temp?

Any pinging is an issue, you could retard the timing 2° at a time up to 4°. More than 4 to correct it I'd look elsewhere. Does it have a heat riser in the left exhaust manifold and is it open?

Reducing the plug gap can also reduce pinging due to a smaller flame kernel.

Good luck!!!

 

Looks like I might have got it.

retarded timing 2 degrees to 8 initial, took her out for a spin, got on her a couple of times up to 70, no more pinging.

I honestly didn’t think 2 degrees would be the Fix but guess I was wrong. Always learning something.

thanks for the help.

got another issue but I’ll start a different thread for that one.

 

25* of mechanical advance is a lot

 

Put conventional plugs back it it, I bet you could put the timing back where it was. The iridium plugs supposedly run a little hotter to kerp them clean so the last the 50k miles or whatever modem plugs are supposed to last.

The other option might be to put slightly header springs in the advance to delay the centrifugal advance just a bit.

 

Not really. Both my 70 and 71 350-4bbl engines points distributors had 10 initial and 24 mechanical.