i have a 9.7-1 comp 572 bbc in an inboard outboard boat , roller cam, 114 lobe centers, dart 345 heads. Motor was dynoed and built by ohio crankshaft for my boat application. Problem is, it runs good wide open but if you idle a little it starts blackening the plugs really bad. The thru hull exhaust is below the water line while idling also. I have tried drilling out the idle bleeds 2 -3 times larger , but still too rich. I have lightning 2 1/8 inch id water jacketed exhaust with 5 inch collectors. I assume ohio crankshaft didnt do anything for the idle while dynoing.
How can i lean and clean up the idle on this motor? It also seems to be a little rich wh ile cruising at around 3000 rpm too. Vacuum is around 5 inches warmed up idling in gear and i have a 45 power valve in front and back. 88 jets square. What to do??????????????