And that could very well, be why nothing fix my problem untel i add the proform metering block to the proform base plate and center section.
I don't know.
So what make you think the base plate is different between the proform and the demon?
Metering blocks will interchange. I'm talking about the location of the passages where the throttle plate and main body meet. Look at a Demon and Holley base gasket and you will see the different slot length.
