corvetero

My engine is 74 L-82 with HEI ingnition and Lunati cam.

I was told that due to the HEI ignition I should be running better R45TS intead the original R44T.

What do you think about that?

Any shorter spark plug version to get some extra gap due to close headers? Accel 576S?

Thanks

76C3forme

GM did change to the "45" with the HEI and I've always been pleased with them (or the Autolite 26's). Quite a number of people have had good results with the Accel shorties, including in the L-82. I've got the stock rams horns so I'm using the '45's currently in the '76 and the 26's in the other SBC. No complaints on either. It's been quite sometime since I've used the Accel Shorties, but I was happy with them in the '78 Z28 (350 - 501/292 cam, headers etc).

corvetero

Thanks for the feedback.

My HEI is MSD one, don't know if that change something....

BTW the Accel shorties are 35. I guess that can be regapped to 45

MelWff

The 576S will give you extra clearance. In addition the S at the end means it's a projected tip plug which exposes the center electrode further into the combustion chamber. The link below explains it.

http://www.ngk.com.au/spark-plugs/te...ion/projection

76C3forme

Not sure about the MSD HEI, but when the GM HEI first came out, the plug gap was initially .060 for that first year / 1974. I had a Buick and the spec was .060. Then the gap changed and remained so (for the most part) after 1974. I'm not aware of any changes in HEI's after that, perhaps there were some issues with a gap that wide.

Most High Energy Ignitions seems to do well around .045 - .055 in most applications.

In most cases you need to gap the Accel plugs (and many others) / or at least check them "right out of the box". Most are close but re-gapping them is not a problem.