the 750 may be small for that...but sure as hell will not stop it from reving past 6100 with little/no load...get the rev limiter

Yep, Bob called my hand on it and set me straight.

Guys, thank for the help, always like to end my threads with the solution I wound up using. Couple of Gary Williams carbs (820 cfm I believe) is what I ended up with. I let him tune (timing and carbs). Acceleration with the new carbs is dramatic compared to the stock carter 750's. Gained a solid 2 mph on top end. Probably from timing and carbs. Cranks easy and idles really good. My engine fluids are running slightly cooler during an honest 100 degree humid day here. I have fuel flow senders, and my mpg at cruised jumped a little more than half a mpg better. I'm happy and proceeding with trying some new props to match up with my rebuilt engines.

Looks to me like you could use some bigger flame arresters. Also is that fuel line 3/8" Coast Guard approved? Looks a little small in the pic.

Good news! I agree with pickle, some bigger better flowing flame arrestors might be a good idea. Upgrading the fuel line to 1/2" wouldnt hurt either. But I suppose if it works, it works. Just don't starve the engines for fuel.

Mild and Pickle,
Gary did suggest a larger flame arrestor. I am limited in height due to hatch clearance. I will search for a larger diameter flame arestor. K&N does not have one that will fit under the hatch, know where to find a good 2" height flame arrestor? I would like to be CG approved. Can you guys expand on the hose might not be cg approved or large enough? The hose is a 3/8" line as Pickle noted. I am attaching a pic of where the fuel line is hard piped from the fuel pump to a lowrance 3/8" fuel flow sender then it is hose to the the fuel log. If my hard line out of the fuel pump is 3/8", shouldn't I be okay? thanks for the tips.

DO NOT USE K&N in a boat, then the ones u have are better then the bioggest K&N ! THEY CLOOG UP !

About the hose, it looks like it might be automotive type hose. To be safe and legal you should have coast guard approved hose. It will be printed right on the hose. It's pretty much just a thicker wall and overall heavier duty hose. If that's just hose from an auto parts store that's not cool. 3/8" should be big enough for what your running.

Yeah, there was a girl in high school with a Pontiac Formula with a 400 in it. Pontiacs would pump up the lifters and float the valves at about 5400. For kicks, we would get in her car and stomp it to the mat and free rev it like that just cause we were mean little turds. Poor motor would rattle for about ten minutes after that as the valvetrain settled back to normal.

My inline 6 in my CJ-5 would self-limit at 5000 due to the ignition points floating along with the valves.

My VW Beetle would self-limit at 5500 due to valve float.

Crusader 454's in a houseboat we once had would self limit at about 6,000. Saw it by accident one day when one of the v drive clutches failed due to a plugged trans cooler line. Not sure if it was ignition (it ran points) or valvetrain, but we caught it quickly and there was no damage from it.

If your BBC's were self-limiting at 6100, it wasn't a fuelling issue - it was limited by valvetrain or ignition. Valves floating (not good at all) or spark strength vanishing (weak coil or saturated trigger). Either way, not at all something good.

MC