I have a brand new holley 750 vacuum secondary carb. the normal idle is 750 for me. if i am driving and i hit the clutch, the idle will only go down to 1000. if i give the throttle a gentle tap, it will go back down to 750 again. i can't seem to find out why it sticks. does anyone know whats wrong?

 

Put on a return spring...and/or a second one.

 

yup, had the same problem with mine. Got another spring on there.

Let me know how that cam runs. When I was building my engine I was debating between that cam and my current one.

 

Put the return spring on the bottom of the carb throttle linkage
and ancor it to the rear. Be sure the spring has enough tension
to return the throttle to curb idle and is inline with the carb throttle linkage travel.

 

That's a good way to wear out the throttle shaft. In that configuration, both the force from the opening and closing are pulling to the rear, meaning the shaft has to react against both forces in the forward direction, causing more wear to the rear of the shaft/throttle body.

If the spring is anchored to the front, it counter-acts the opening force without making the throttle shaft the folcrum.

 

(hit wrong button)