Spark plug heat ranges

[Ricko1966]

Yes I’m having a problem with fouling plugs, have been running stock heat range of 41 but upgraded the distributor to a Davis Unified that recommends wider gap on the plugs so now I’m fouling stock heat range plugs. Will increase heat range to get where I need to be, I appreciate all the help!

Put the gap back where it was and see what happens. You replaced a part and developed a problem,not certain that that is an upgrade I'm not a big believer that everything you buy is better than what you had.

 

[Grit dog]

Never heard of a 41 Delco plug, stock. Those are cold.
But are you sure it’s the plugs? Depends how they are “fouling”.

 

[82BBC20]

41 is definitely cold, I’m going to go with a 43/44 haven’t decided yet, their gapped at 50 now which is what Performance Distributors called for so definitely going to close that up some also.

 

[Rusty Nail]

Makes me wonder...hey OP did you happen to start magically fouling plugs coinciding with a change in fuel octane or brand? Perhaps is E10 to blame?
How about the switch from summer to winter blends playing a role? Is your pickup in otherwise good running condition or are the valve guides beat?
Does it smoke on start up?

It makes sense to seek a "hotter" range of plug or a stronger spark but that won't fix a broken valve guide. Heat range really is about degrees of camshaft timing and operating range.
Spark plugs are how to  tune engines, not repair them.
What other changes happened before you bought a new distributor and why did you think that would fix it? Are you certain that it is installed and adjusted correctly? How do you know?

In my experiences as an auto mechanic lots of light can be shed by looking into the past  especially when the owner has popped the hood with tools in hand. Nothing personal old boy but I only report facts. So let's have em.

There ain't no good reason to start fouling plugs out of the blue, there are some other factor(s) in play. Something else changed beside the distributor we haven't looked at.
Got a valve tap? Been messin with the rocker nuts? Swap intake manifolds lately?

What kind of oil are you using and is it overdue for change?

 

[Ricko1966]

Makes me wonder...hey OP did you happen to start magically fouling plugs coinciding with a change in fuel octane or brand? Perhaps is E10 to blame?
How about the switch from summer to winter blends playing a role? Is your pickup in otherwise good running condition or are the valve guides beat?
Does it smoke on start up?

It makes sense to seek a "hotter" range of plug or a stronger spark but that won't fix a broken valve guide. Heat range really is about degrees of camshaft timing and operating range.
Spark plugs are how to  tune engines, not repair them.
What other changes happened before you bought a new distributor and why did you think that would fix it? Are you certain that it is installed and adjusted correctly? How do you know?

In my experiences as an auto mechanic lots of light can be shed by looking into the past  especially when the owner has popped the hood with tools in hand. Nothing personal old boy but I only report facts. So let's have em.

There ain't no good reason to start fouling plugs out of the blue, there are some other factor(s) in play. Something else changed beside the distributor we haven't looked at.
Got a valve tap? Been messin with the rocker nuts? Swap intake manifolds lately?

What kind of oil are you using and is it overdue for change?

He started fouling plugs when he switched to an aftermarket distributor and opened up his plug gap. I told him close the gap back up and see what happens. If it was mine first of all I wouldn't have gone to an aftermarket distributor, but if closing the gap doesn't fix it, Id put the stock distributor back in. If my new shoes hurt my feet I'd put my old shoes back on?, not cut off my toes.