@DannyP thats just how mine is mounted, pretty much the same except the extended block under the throttle connect. The Vibration is still present around 3,700 to 4,200 rpm. Vibrates on the gas pedal is pretty annoying, so far I've played with adjustment at the pedal, and also added some rubber fuel line around the cable where it goes through the body and also turns up from the bottom of the engine and uses a prober clamp to hold in place. No luck.
Next up is to add a rubber gasket to the mount where the connector bolts to the transaxle to see if vibration is getting transmitted to the cable?
Going to also see how the carbs sync at 3500 to 4000 and see if its off and may be causing the motor to not be pulling correct? I don't feel it in the pants while driving but maybe???