why is my edelbrock 650cfm cutting out at wot?

Fuel pressure good? float level correct?

my mechanical pump is kind of old but pressure seems ok. my float level, i havnt touched. adjust how?

Before tearing carb apart check fuel pressure and flow. 3 to 5 psi and pint in 15 sec

it depends on whether this is a avs styleor afb. i thnk it's an avs style that acarter used way back then. You will have to check the rear blade to see if it's opening to fast, there is or shold be an adjustment on the side for it. Look at your instructions or contct edelbrock i'm sure they have instructions on the net. Or yur metering rod may not be opening all the way.and i dont' remember if it h as a pwer valve or not, those are the ususal causes.