Spark plug gap

[86suburbanNJ609]

I set my spark plugs at .45 on a 350. I see guys saying .35 am I doing any damage to truck? Should you against the chevy recommendation?

 

[Charlie]

I used AC Delco R44T gapped at .035 per specs. When I switched to HEI distributor gapped at .045 due to the hotter coil. I had read many people state that it was ok. You are probably ok at .045, with oem distributor, may not be as efficient as .035. Just my observation of various forum members.

 

[idahovette]

If I remember right when GM first came out with the HEI system they were gapping at .060. (74)? Then they went to .045

 

[Charlie]

If I remember right when GM first came out with the HEI system they were gapping at .060. (74)? Then they went to .045

My 74 had oem distributor (points). I upgraded to HEI. From info that I found, GM came out with HEI beginning in 75. Did not know about .060 gap. Seems quite a bit much, IMO.

 

[idahovette]

My 74 had oem distributor (points). I upgraded to HEI. From info that I found, GM came out with HEI beginning in 75. Did not know about .060 gap. Seems quite a bit much, IMO.

Yeah you may be right ,it might have been 75. We had a farmer who bought a new 75 C-10 454,400 a/c ps everything and had nothing but trouble with the ignition system. We put it back to a point dizzy and problem gone! Bad modules and lack of knowledge on every bodies part.

 

[PrairieDrifter]

I’ve always gapped at .045

 

[bucket]

I’ve always gapped at .045

Me too. If GM hei, I give them .045 no matter what the books say.

 

[Chevyguy]

I always go by what the emission sticker says to gap them to. Just helped a neighbor with replacing the coil, and ignition module on his 84 GMC K-2500 yesterday afternoon. Red wire on the coil was burnt just about through from arcing. Fixed that with a new ground strap on the new coil. I like my 87's ignition better with the coil mounted on the intake manifold.

Clayton

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[78C10BigTen]

My complete stock 350 with an HEI ive always gapped at 35. I switched to E3 and they cannot be gapped so idk what they are now.

 

[Chevyguy]

My complete stock 350 with an HEI ive always gapped at 35. I switched to E3 and they cannot be gapped so idk what they are now.

How do the E3's run?. I have a set of Autolite Double Platinum's that I'm going to try.

Clayton

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[78C10BigTen]

How do the E3's run?. I have a set of Autolite Double Platinum's that I'm going to try.

Clayton

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They ran alot smoother when first put in. I honestly dont see too much improvement over what i previously had. But im suspecting my distributor is bad also.

 

[Chevyguy]

They ran alot smoother when first put in. I honestly dont see too much improvement over what i previously had. But im suspecting my distributor is bad also.

Might need a rebuild if it isn't too worn out.

Clayton

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[78C10BigTen]

Might need a rebuild if it isn't too worn out.

Clayton

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Im gunna buy a skip white.

 

[85 CA SIERRA 1500]

Im gunna buy a skip white.,

PLUS ONE on the Skip White HEI, I have been running one for the last 10,000 miles or so and it has been absolutely perfect,