Originally Posted by Deve
I guess I can see improved gas mileage since it burns hotter and more cleanly, but I do not know.

I have this same problem for pretty much everything I create. Limited funds such that I can't just send parts to the willing to test them. Its why I include a parts list and complete instructions on how to do it yourself with everything I do. If I can be of any help otherwise I am always available.

The people that said better MPG went straight to plugs with gaps that were about double of the original gap.

So to claim how much was due to the HEI or plugs has never been found out.

Controls needed: Stock ign with stock SP gap.

Stock ign with increased SP gap.

HEI with stock SP gap.

HEI with same increased gap.


I hear you when you say limited funds. If I did not have my son's truck to work on I would not be involved in the antique car hobby. That's why I said I wish I lived close enough to of worked on this with you. Cause not only to get to play at being an inventor you are able to do so while allowing things to easily get changed back to original.