Griff

A 741 cam is going to keep making more horsepower up to at least 5500 rpms.

Like was said, way lean on the AF for a boat. For a drag car, it would be fine, but sustained rpms in boat are going to melt something and cause detonation.

ubet28

So will the index regulator help with the problem or what should i have them do?

Also will the bottom end handle the 5500? All stock parts out of the 500. Merc says 5250. Thanks Griff

PatriYacht

I agree, it needs to be revved higher. With those heads and that cam and a supercharger, it won't peak until it starts to float the valves. Probably around 6000 rpm. Looks like you have about 800 hp up there. Congrats. Way too lean. Like the other guys say. With the wrong AF ratio, you can put holes in the tops of your pistons the first time you try full throttle. Not a good way to start the season.

PatriYacht

What do you mean index regulator? With a roots blower there is no need to index the fuel pressure regulator. Just make sure you have @ 7 lbs at all times. Boost referencing the power valves is something you might want to have done. Larger main jets on the secondary side about 4 sizes to start also.

PatriYacht

One last thing, is your oil cooling system up to the task of removing all of this extra heat? If it's not, one minute of full throttle will put your oil temp at 300 degrees and weld bearings to crankshaft. Until you get to know this engine, keep a close eye on your oil temp gauge. When it hits 280, back off. I guess the reason I'm worried is because running lean causes high oil temp as the heat is passed thru the top of the piston. If your oil cooling system is marginal, running lean makes it worse.

niceguy

Excellent advice PatriYacht.

PatriYacht

Thanks, Niceguy

kennyo

Definitely get the A/F right in the boat! Oil temp gauge and sufficient coolers also a must. Every one here giving advice learned it the hard way. Take a chance and you will too! By the way it cost me an engine for each one of my suggestions!!!

Griff

I don't know what you are referring to as the "index regulator"

The bottom end will handle 5500-5800rpms just fine. I spun my 454mag with an upgraded cam to 5500rpms.

PatriYacht

The bottom end is fine to 6000 rpm. The weak link in any BBC is the valvetrain. That being said, without a cool, clean, unfoamed supply of oil at @ 60 lbs. it will have a short life.