351c tunnel ram

hi from nz cool site ( : got a problem 351c with twin tunnel ram (cain) twin holley 450s port matched manifold to heads headers unsure of internails of engine pretty stock with possible mild cam sorry for lack of info car was in the begining found to have 2 or 3 cracked plugs all plugs including cracked ones looked very lean white and hot was missing bad accepting only light throttle replaced all plugs with correct ones still pretty much same next found blockage in rear carb shooter etc found pump diafram center rusty?? also both secondry float bowls empty or very low??so cleaned carbs filled bowls to standard level adjusted idle mixture now! car is fouling plugs still wont accept much throttle spits out the carb ive done a little research would i be right to think either blown power valve/valves /shooter size/floats to high/air leak manifold/ blocked air bleeds in carb/ also thought that maybe broken/wrong plugs and blockage was only problem should i empty secondry bowls again is this normal? we put new plugs in she growled but fouled them 1km up the road havent had it going right yet any help would be great. thanks all

sounds to me like the engine has WAY too much gas coming in for the setup.... a tunnel ram is a pretty extreme intake and if the motor isn't extreme to match it... all you're gonna do is run problems.... sounds to me like the guy before you had it set to be pretty leaned out, cause thats about all he could get it to run right with.... i'd say try and get it to where he had it, and then make it run with just a tiny bit more fuel