question For Tom V.
 

Tom what causes blown cars to do the high /low cycling when they Idle ?, I even seen some street cars with blowers do the same thing is it from the carbs recieving a pulsed vacum signal from the blower ? thanks

I assume you are referring to the "Rump" and then you wait a couple of minutes and another "Rump" etc Just Kidding. It has to do with the blower speed, the camshaft events, and the carb/injection calibrations. Most carb set-ups are very rich unless the carb has the remote Power Valve signal mods that allow the carb to see vacuum below the blower. Typically with those mods the carbs will supply fuel correctly and will use smaller jetting.

Even though it "sounds cool" the car/engine will be faster with a more refined calibration typically.

Tom V.

thanks tom .. I have seen injected /blown cars Idle smooth as a stocker but the carbed ones alway did the surging I thought it had something to do with the vacum signal/fuel mixture but wasn't sure , as for the rump back up thing and rump again ...hmmmmmmm..... :)