Ok, this is my issue. I have a very well built 393W, solid roller lifter cam in the 290's for duration, and .585 lift. AFR 185 heads that have been port matched to my Edelbrock Performer RPM. All valves are set at .020 with the engine at full operating temp.
I have a Mighty Demon 750 carb, and the thing is pig rich, eye watering, black smoke coming out the exhaust. I have checked the vacuum at idle and she sits at 11-12 pounds. The power valve is new, and a 6.5. I have downed the jets from the stock 75's to 70's and it made no change. I have set the throttle plates down as low as I can, and adjusted the idle mixture as lean as I can.
It's still rich, and all the plugs are BLACK.
When I pulled the Demon apart, it had aluminum swag in almost ever orfice left from the CNC machine. I completely cleaned all that out, but it really made no change in the performance of the carb.
Could the carb just be crap? It's my first Demon, and all the Holleys I have ever run worked great.
I have also checked for vacuum leaks, and found none on the top side of the motor. The heads were not milled, but there is a remote chance that it's bleeding from the underside of the intake. Would that cause my rich condition, or just lean out the mixture?
I am about to order a $400.00 Holley 750, and just get it over with, but I am really bummed that my $500.00 Demon is a paper weight!
Any advice, or help would be greatly appreciated.
87
I have a Mighty Demon 750 carb, and the thing is pig rich, eye watering, black smoke coming out the exhaust. I have checked the vacuum at idle and she sits at 11-12 pounds. The power valve is new, and a 6.5. I have downed the jets from the stock 75's to 70's and it made no change. I have set the throttle plates down as low as I can, and adjusted the idle mixture as lean as I can.
It's still rich, and all the plugs are BLACK.
When I pulled the Demon apart, it had aluminum swag in almost ever orfice left from the CNC machine. I completely cleaned all that out, but it really made no change in the performance of the carb.
Could the carb just be crap? It's my first Demon, and all the Holleys I have ever run worked great.
I have also checked for vacuum leaks, and found none on the top side of the motor. The heads were not milled, but there is a remote chance that it's bleeding from the underside of the intake. Would that cause my rich condition, or just lean out the mixture?
I am about to order a $400.00 Holley 750, and just get it over with, but I am really bummed that my $500.00 Demon is a paper weight!
Any advice, or help would be greatly appreciated.
87