I have a Holley 750 (4160) with vacuum secondaries and a metering plate on the secondary side. I want to install a metering block to convert the carb to a 4150 for better adjustability. I have a friend that has a secondary metering block off of an old carb and he was going to give it to me to try. The plate has provisions for a power valve as well as jets. Can I use any secondary metering plate or should I look for one with certain part numbers on them?

Yes, no, maybe so?? :D

you can use it but will need new fuel inlet line.

Yeah, when you order the kit you get the longer fuel inlet.