proform race carb / Idle trouble

Most std holley metering blocks are not adjustable. You either have to drill them out or remove and tap for a 6-32 set screw.

If they are andodized alum or aftermarket blocks, they are usually adjustable.

I didn't notice if you had 4 corner idle or not, but if you have a 73ish secondary IAB with a 2 corner idle, that's going to be really lean.