another low budget 454...

hey all. im kinda running around in circles. my 402 had issues so its out of the car. i have a chance to grab a running 79 454 with 1500(rebuilt) miles on it for $500 i plan on changing the stock intake to an edelbrock rpm airgap. and a 780 holley avenger (i already have these parts) not too sure what to do about the cam /lifters/springs yet. but my biggest question is this. do i keep the stock rebuilt 781's? or use my fresh 290's? they have 2.19 x 1.88 valves and have some mild porting, and are gasket matched. im trying to stay less than $2000 for the whole package.