I dont think the 14 deg at idle is the problem. Mercs supercharged engines idled at less than that . It certainly will idle better, with more timing at idle, but not the issue with it blackening plugs, popping, and overall running like chit. Nor will the carb cfm.

I agree with mike t, twin 850s would be my choice if buying new

Are you sure you have all the valves adjusted properly? What procedure did you do when adjusting them ?

I read through most the post however may have missed a couple but if you haven't do a comp test and leak down. ck out your grounds... Sometimes it's just completely different than what you'd expect. Wiring harness? Mice? i hear what your saying with the carbs. Regardless of size this shouldn't be doing what it is plus you've eliminated that. Along with your grounds make sure any hot wire isn't touching or arcing anywhere.

Do me a favor and run it in the dark on the hose or whatever and look around for any of the above. Arcs etc show up well when the lights out plus you can have a beer while doing it. Just trying to help. Ck everywhere including your plug wires and plugs. Do it in the dark. Other thing is possible your throttle wires etc. neutral safety switches shorting. This could just be a coincidental deal going on and not related to your new good guy parts.

Ok, we went back to normally aspirated setup. Air gap intakes, holley marine 750's. The only "new thing" we had was the msd pro billet distributors, and the new plug wires. Cranked on Port motor (the one we've been playing with the whole time), same thing. We got the starboard motor read and fired it, same thing. We pulled the new plug wires off the starboard motor, and put the ones we ran last year on there. Same thing.

I went and got my old accel HEI distributors, installed on the starboard motor, problem solved. Shon''s wiring the old HEI in the port motor now. I'm not getting what the problem was. We had them grounded on the soleoid ground on the back of the motor. I never did check the ground with a meter, but good grief I don't see how it would not have been a good ground. Maybe I'll check later in the summer, and reinstall the blowers, but right now I'm satisfied just knowing it was something to do with the distributors, and the boats running right. (fingers crossed on port motor)

sucks that you jumped the gun and pulled the blowers off.

Fukin MSD. Excuse the french.

Rust, module issues....
Case in point, The other year some of their distributors where coming with the wires wrong in the connectors.

Hei dui flame throwers here. Been down the other road and would always seem to be chasing something.

Everything happens for a reason is one way to look at it. It just wasn't meant to be at this time.

Port motor runs also runs awesome with the old HEI ignition. Got the timing set on both of them.
I know Mild Thunder, I hate that we pulled the Blowers off but at least it's running right now. And I had no idea what the problem was. I just can't hardly believe that two brand-new distributors were messed up. I had convinced myself that it had something to do with the set up, the Head's or the cam not working with the blower or something.

MSD - Might Soon Die