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enaberif · 05-03-2016, 08:35 AM

Spark plug gap on a HEI Chevy should be .045 as .030 was for a points system. Yes using the wrong gap will make a vehicle run like absolute crap. When I put plugs in my truck they were gapped for .030 and I could not get it to run properly no matter what.

Also doing vac gauge measurements I am pretty sure it should be on manifold vacuum not ported vacuum as should your distributors vacuum advance to get optimal performance.

05-03-2016, 08:35 AM	#3780
enaberif Registered User Join Date: Jan 2009 Location: Calgary, AB Posts: 1,181	Re: Restoring Rusty Spark plug gap on a HEI Chevy should be .045 as .030 was for a points system. Yes using the wrong gap will make a vehicle run like absolute crap. When I put plugs in my truck they were gapped for .030 and I could not get it to run properly no matter what. Also doing vac gauge measurements I am pretty sure it should be on manifold vacuum not ported vacuum as should your distributors vacuum advance to get optimal performance.