| | New 408 tuning
My question is I'm tuning the carb and it is running rich at slow speeds but good mid to high. Checking the plugs and they got that real nice tan look, but still can see some carbon build up around the inside of the plug. I dropped down four jet sizes in the front and left the rear alone. If I let it sit and idle it doesnt load up. When I drive around slow it loads up and spits and pops out the pipes. It will clean out when you drive at normal speeds. I'm thinking power valves are opening real early. My mech vacume gauge says 20" the lap top says 5" on the MAP sensor. I have a MSD timming box. I'm thinking of trying a 2.5" PV and a 10.5" as well and compare plugs, it has 4.5" in it now. Also the rear has a power valve I think I might plug it and just tune the rear with jets. The carb is a holley 950 ultra HP mech secondary, double pumper. Any advice? Also this is a new motor, I'm just starting to tune on it. I played with the timing a bit and the curve 6 works well. The motor runs great, other than the loading up.