i sent my carb to Sparky's carb service. he needs a vacuum reading from my manifold at idle and at a higher RPM. i am wondering if i will have the right reading for him. the carb i sent him is the 7040250 that belongs on my car and the carb on my car is just a reman from autozone. if this carb is a differant CFM will that affect the vacuum reading? also does anyone know what the vacuum reading is on the stock 310 HP engine? this has
15 in hg at idle and 19 at 2000 rpm and higher. i have an aftermarket cam in mine.

 

I would to talk to Sparky's. They must go through this all the time? Best thing would be to get the vac readings with the carb you sent but if it needs rebuilt and won't work it's a Catch-22 situation? What if you're switching over from a 2 barrel and have never had the carb on the engine or have a Holley or something like that?
I bet he wants the vac readings to get an idea of how much different it has to be than the norm because of engine modifications, otherwise would probaby just rebuild it to stock specs. I wouldn't think the carb would effect the vac numbers that much if it's adjusted correctly and all that, but I'm no engine or carb expert, that's for sure.