quiestion about a stock hood with rpm airgap?

Edelbrock gives the dimensions of the RPM Air -Gap. Measure the stock intake and compare. Important... A/B Measurements
CHECKING FOR HOOD CLEARANCE

To ensure adequate hood clearance, check the height of your stock manifold and compare the "A" and "B" measurements against those of the Edelbrock manifold prior to purchase. The heights of all Edelbrock manifolds are listed under "Installation Notes" for each model in the intake manifold section of this catalog.

Please Note: To figure carburetor pad height, add dimensions "A" + "B" and divide by 2.

For example, Performer manifold #2101:
(A) 3.5" + (B) 4.6" รท 2 = 4.05" The difference in mounting height of the air cleaner( if any) between whatever carb came under that cleaner and the carb you have now will need to be accounted for too. Then you'll know what's up before you put the hood on. Good Luck