I just had a 468 Chevy built this spring and it has a new Holley 850 marine carb and I just replaced the mech. fuel pump with a Holley 110gph because I though maybe it was starving for fuel on the top end. Everything is brand new on the It will run a solid 4800 some times and drop to 4500 then 4300 and hang there I also put a snap on digital tach on it and same thing so my tach is spot on. Any ideas whatI should be looking @ to correct this. Any help would be great!

That should be way more than enough carb for that motor. Whats your fuel pressure at WOT ? Are the floats adjusted properly ? Did you pull out the restrictive filters that are in the bowls where the fuel lines connect ? Are you running a water seperator/filter combo (the screw on type) ? Make sure that is clean...and remember (most people dont realize this) that you can put alllll the pump you want in the boat...but most of those water seperators only flow about 70-90 gph at best. You can get bigger inlet and outlet lines for this filter (its 1/2") Perma-Cool 81794 ...or if your feeding 8 squillion Hp...you could get this (3/4" inlet and outlet) Perma-Cool 88864 !!!!! Remember, anywhere you have 90* fittings, or have the line necked down, is a restriction.

Im having the same problem. My next step it to take the fuel pick up out and see if the sock is plugged.

I could be wrong....but I've never heard of a sock style filter in a boat tank. That's more of an automotive thing. I could be mistaken tho (wouldn't be the first time...lol).

Ive never seen one either, Just a straight pipe to the bottem of the tank. Just had mine out this weekend to cut them shorter.

I seen you @ Liberty working on her any luck?

I have a stock Merc water/fuel seperator yes. I have not tried any of these solutions but I will thanks!! No 90* anywhere. Again thanks for the reply!

Still chasing a ghost!

I hear ya I'll let you know if I find anything out.

I think we may have it. Alternator shorting out sucking power. not enough spark.