what is it? how would i go about telling if i have it?
Also is it better then i guess i would say standard?

 

high energy ignition, if you don't have points or direct ignition then you have hei. if you have a thirdgen f body you have hei.

 

only really reason im asking is because the motor came out of a 75-77 pickup 350 ci and i was buying plugs and they ask if i had hei but i got lucky they their both the same.

 

on the older HEIs, including some on 3rd gen f-bodies, the coil is in the top of the cap. i cant remember the year when they started using, HEI but it was the mid to late seventies...i think either 75 or 77 ( i am leaning toward 75),

 

75 was the first year for HEI .

 

HEI was GM's trade name for electronic ignition. It started in some 74 cars (I know, I had one, a Monte Carlo with a 400, we boughtt it in 77) and was in all cars starting in 75.

For a few years right at fist, they were telling everybody that they could gap their plugs at like .060"; so AC and others came out with plugs pre-gapped to that. After everybody's car went through a couple of rotors, we all got tired of that, and GM did too, so instead they started recommending .045". So that was the "difference" between the plugs.

 

cool thanks. Is there a way to tell if i have it or not?

 

Is your car a late 74 or newer?

Does it have the stock distrbutor?

If yes, then you do.