4 hole carb spacer for better signal, will it work?

[hugger6933]

I've had good luck with all my MSD stuff though I never have had [to my recollection] a dist like yours. I think you have a lean condition off idle, and yes the 750 will work while a little big it will do once tuned out. Check the power valve those blow out any time you have a backfire and it will cause troubles. Try another power valve and then maybe work on adding some more shot at the pump by moving the pump cam or adjusting the pump arm.