Dan,
I run the Jacobs Pro Street and I have the best results with Autolite plugs. I have played with gap settings and get the best results at .048 - .049. I use 3924s and have really good luck with them but yours is a Cleveland and it would probably take a different number. Also I tried platinum plugs and they worked very crappy. The Jacobs manual says just use the regular type electrodes as the others throw off the resistance measurements.
Ron
