I was forwarded this thread from a friend who saw me go through some of this... I bought a boat with a 502 with a 250 B&M on her. I leaned out and blew the blow off plate on the side of the manifold and waisted a valve. I ended up ripping out the motor punching it to a 509 and putting J&E pan pistons in her. I junked the Thunderbolt 4 and put MSD in with Crain Fireball coil and MSD 6 box. locking her out a 28 degrees total, no initial. I run a Nickerson 1050 carb and I ended up having to make 2 dips into the tank running the stock fuel pump and one electric fuel pump. I ran them into the fuel separator and then into the regulator, with separate fuel lines to each bowl. I run 7.5 pounds of fuel pressure. I run 7lb of boost on the blower, the fuel pressure never drops lower then 5.5 lbs. The B&M intake is kind of thin and could crack very easy... I hope some of my info may help... Its not much but the motor runs and performs awesome now.

Thaks H2O mine is performing pretty well gonna play with the props a bit this wekeed hopefully and get a little more speed from it or at least a better rpm range. Just looking to find the coolant leak thats my maine objective.

Glad to hear you got her running good...I hope you find the coolant leak soon...and its a cheap fix!

Me to but main thing is just to find it the money thing nothing really can be done what it is it is

What manifolds are you running... I fond a leak between my manifold and my riser.. It leaked down in between the black.. what had happened was I tightend down the riser to much and caused the middle of the riser to lift up letting the gasket leak...I was not an easy find cause at idle it would only drip down out the bottom...

ME....

Im runnong stainless marine. This boat was already put together for a while just happen to happen just as i got back from block as i entered the marina (thankg god it wasnt in the middle of the ocean) Yea idlea its fine and under pressure i cant find anything either, holds presure its just as i run it but under load not just the engine running, o well hopefully found soon.......

It won't be the manifolds raw water goes through them. I was thinking what if you or us take my old video camera and aim it at the tank tape it down leave the lights on and run up and down the river smooth water and watch the tape if the camera breaks no big deal its 4 or 5 and it took a beating last fall on my boat . so we can zoom in and watch the hoses at different spots or I will crawl in side with the lights on and feel for leaks and mike I GOT A CD WITH YOUR BOAT ON IT AND NAME ART

That would be raw water in there this is a hose, hose clamp, cap, or tank, engine block shut off on either side lower block. art

MIKE THATS IT what about the screw in sea cocks on each side of the block they are lower by the stringers we or I was thinking high by the hoses or tank, LIKE I said I can come down and lay in the bilge and you run it or the camera in there I always wondered what a bilge felt like at 80plus . art call me

Thanks art checked them, all tight i cleaned the coolers we'll try that