Napa doesn't understand spark plugs.

[heviarti]

I've been ordering spark plugs by application, and it occurred to me that might not be correct for two reasons:
One, I have an engine that has had all of the superfluous hardware removed. Without emissions the mixture is slightly different than an engine with both PCV and EGR.
Two, In 1970 the small block was making 370 horse in one iteration. The more I can do to be closer to what was supplied with that, the better.
I asked the folks at napa about spark plug heat ranges; figuring that with the removal of all the crap from the engine, it would likely be closer to a pre-1972 configuration, I asked what heat range the plugs used in the 1970 truck were. Apparently they used what they are calling a 'peanut' style head, which requires a plug with a sealing ring. Since the plug application for the 1979 calls for a different plug, they said they were unable to compare the heat range. Call me dumb, but aren't there charts to do just that?
Does anyone here know this, or have some of the old charts? I asked the dealership's eldest mechanic the same question, and he could not answer either.
I understand that the plug heat range has nothing to do with the spark, rather that it just has a bearing on how much heat is retained or dissipated by the plug. If my engine was intended to have EGR (more moisture and carbon) and PCV (more moisture and oil vapor), then the plug should be geared with that in mind. Without either of those, I should have less material to deposit on the plug meaning a colder range, but without actually being able to compare the application i'm working blind.
It also seems like the most of the plugs I find are coated with what looks like a black oxide finish. With a colder plug I'd want something more like an electropolished finish, to discourage deposits that its surface temperature might not burn off, right?

 

[87scotty]

To much thought lol

 

[rich weyand]

ACDelco R45TS or Autolite 24. .045" gap.

This for non-emissions small block with HEI.

 

[MikeB]

Using the plug for a solid lifter 370hp 350 Corvette/Z28 engine will probably work OK, but its heat range may be a little on the cool side relative to a lower compression Impala or pickup engine.

Are the plugs you need 13/16" hex with a sealing washer, or 5/8" hex with a tapered seat?

 

[heviarti]

5/8. I'd have replied sooner, but every time I try I get a no data response from the server. I have added an MSD cap and rotor, an Accel HEI super coil, and 10.4mm Thundervolt wires. It seems the more spark I feed it, The more the thing misses... @#$%R chevy...

 

[firebane]

5/8. I'd have replied sooner, but every time I try I get a no data response from the server. I have added an MSD cap and rotor, an Accel HEI super coil, and 10.4mm Thundervolt wires. It seems the more spark I feed it, The more the thing misses... @#$%R chevy...

Your throwing money at the truck for no good reason. Stock HEI systems working perfectly out for the majority of builds out there.

People insist on putting aftermarket coils, and big plug wires and blah blah and wonder why things don't work.

Get a OEM distributor with a good coil replacement from NAPA and put some decent 8.5mm plug wires on and call it a day.

If it still misses after that you need to look at other problems.

 

[Georgeb]

Your throwing money at the truck for no good reason. Stock HEI systems working perfectly out for the majority of builds out there.

People insist on putting aftermarket coils, and big plug wires and blah blah and wonder why things don't work.

Get a OEM distributor with a good coil replacement from NAPA and put some decent 8.5mm plug wires on and call it a day.

If it still misses after that you need to look at other problems.

Agreed!

 

[87scotty]

Also having err connection area 90% of the time I click on something won't let me make a thread to post this problem and can't go to more pages I'm lucky if it opens help admin!