Interesting, I know of a someone who had a combo close to yours with about the same HP as yours too....a 509cid engine with Dart Iron Eagle 308cc heads with just some clean up in the bowl/pockets of the heads, Air-Gap intake, and Crane 741 cam and made 563hp @ about 5600-5700rpm on Tyler Crocket's dyno with dyno headers about 6 years ago.

I would think a bit warmer thermostat might help as well. Also, look for a needle/seat that may be sticking a bit in the float bowls....it doesn't take much to make a needle get stuck---just a tiny grain of dirt can do it. It gives the same symptoms as a blown power valve where you have a slow drip from the booster.

That really depends on where the oil temp reading is being taken. The oil needs to be at 212* at some point to properly burn off condensation.

I just reread your initial post RBT. I thought you had an Edelbrock carb :drool: Water temp is not an issue on this engine. I'm running 120 degree therm's on my engines with AFR alum. heads and 1050 Holleys and they will idle at 700 rpms all day and not foul. A 741 cam is a large cam for a 502 but it is common and a good power maker. It should idle at more like 10 in. How many rpm's are you idling at? You may have to turn up the idle some. If the timing is set for 16-18 dgrees initial and 34-36 total, the next thing I'd check is the carb. Standard power valve is 6.5. Under 6.5 inches of vacuum it is open. Changing it to a 2.5 will end that problem. Have you ever checked the float levels? Needles and seats? What are the jets?

Kaama, I just looked at the dyno chart last night, 562.9 Hp at 5500 rpm. I forget the torque numbers.
PatriYacht, the boat is away for it's winter nap. It is in heated storage for the winter and I am going to make some changes over the winter.
I am going to get all the numbers from the carb and convert motor from crossover cooling to a recirc setup.
The current water temp in the summer with the lake at about 80, is 120 at best. The oil temp does rise if you are on the throttle to 240/250 which is hotter than I would like to see. It has a 2" X 10" oil cooler, the temp is picked up off the block.
Oil is Merc 25/40.
The motor idles at 800 rpm.
The spark plugs are NGK 5587, the other number on the box is R5671A-7
If I have not also stated the intake is a Victor Jr, exhaust is Imco Power flow, with BIG inline mufflers.
The ignition is from the old 330 that was in the boat, total timing it 34 degrees.......so what does that mean for initial?.... I have a V6 module from a blower motor I had.

Thanks for the help.

RT

I'm pretty sure the V6 module gives 14* of advance, that would put your initial @ 20* if you're running 34* todal.

Something is still not adding up with your vacuum being that low. check to make sure your carb isn't miss adjusted and the secondary butterly is open....either that or you need a small powervalve such as a 2.5.... but like I said before, I put a 6.5 in my friends 850 carb and it's a 454. something seems strange.... Maybe you have an intake manifold leak or something?

I wouldn't even worry about the circ. pump. With that much power I think you stand better having a crossover. If anything buy a crossover kit with a t-stat so you can run 140* water temps.

Your oil temps...are they at cruise speed or WOT?

Oil at cruise is 180-220 depending on how long it runs.

The motor needs more heat in it...... I think. The inside of the valve covers is caked in milky oil. The engine oil is fine though.

If you run a crossover kit with a bypass for a t-stat and a 140* t-stat you won't have any problems with condensation. I'd go that route before putting on a circ. pump. IMHO, the circ. pump is one more part that can fail on you.

Your oil temps are fine IMHO...

What are fine oil temps, I mean how HOT is too HOT?
I think it will see 250-270, I am thinking of going to synthetic.......thoughts suggestions?
Oh and I should mention that I run all season, so that is water temp from in the high 30's to low 80's, Brownie at Stainless Marine didn't think the crossover was a good idea.

Thanks
Keep the info coming, I am learning.

240-260 for an exteded WOT period is fine. If you run synthetic tou can go a bit higher. If youre running those oil temps (220) @ cruise you should also be burning off th moisture.

I still don't think you're fouling plugs from a cold engine unless the plugs are too cold to begin with.

The only 2 plugs that I am fouling are the front 2, where the water is the coldest. As you pull the plugs and move toward the rear of the motor they look better and better.
My bet is that is heat related.