I have a ZZ502 and it came with a holley 850 vacuum secondary carb. I took it off and installed a speed demon 850 with mechanical secondaries. Right now it is jetted at 80 primaries and 88 secondaries.. I think the primaries may be ok but I think the secondary jetts may be too big. It acts like it may be getting too much fuel when I open the secondaries. Anyone have any advice on jetting for this application? It is street driven, no race tracks...Thanks

For your elevation, I would come down on both about 4 steps and check your pv #. 65 should be right. Then go from there. You are about 3500ft above sea level? If you have secondary idle circuits , you will have to readjust both. Unless you have rough camshaft, I will guess your Idle EZ does not work?

My elevation is about 800ft above sea level...

My elevation is about 800ft above sea level...

Think you still could be too rich. Just have to do some back to back runs to get it right. Do you have an air flow meter? Wideband? What are plugs telling you?

No, No and I haven't ck'd the plugs.. I'm going to jet it down to 86 on the secondaries and see what happens...