VetteLT,

I thought about that, too. I just checked mine, and it's a flat head cap screw, with the hole in the drive plane countersunk, so that the bolt head is flush with the bottom side.

Thanks. Brad.

Wires and plugs were all good! I was told iridiums suck with an msd system and the put out a weaker spark then copper.

Summer89,

I tried the E3 plugs a while back in my old boat, trying to find some diminishing RPMs. After making the purchase, I was told by multiple people to just stick with the old reliable ACDelco MR43Ts. I was essentially told that anything beyond a “spark plug” was nothing more than marketing fluff. I got that from here on OSO, from one of my local reputable speed shops, from Mercruiser…. On and on. I’d say if you already have them in there, let them ride and see what happens. Can’t tell you where else to look, but I can’t imagine it’s your drive shower pickup.

Food for thought.

Thanks. Brad.

Not knowing the specifics of your MSD ignition setup I would verify that the plug gap is correct. Those plugs typically come pre-gapped for automotive application. Also don't discount all the simple things such as freshness of fuel, changes in the weight distribution, things like that.

Don't sweat it, just be methodical and backing out or verifying changes. I once added a B&M 250 to my HP 500 and lost 5600 RPM but I also gained some ventilation in the oil pan but that was only after 6 years of use and one rebuild in between. Went back to an NA motor and put several hundred hours on it, now all I do is change the oil, check it, lower hatch and add fuel.