Need some advice, installed roller rockers on my 1966 396,had to go with taller valve covers,now the drivers side cover won’t clear the new brake booster because it’s mounts project it farther forward. Does anyone have any ideas?
Welcome to the Team Mick!
Don't buy aluminum roller rockers. The aluminum work hardens and cracks, and they are too big (made bigger because aluminum is a lot weaker than steel) to fit under a stock cover. Also it is probably the adjustment nut that is hitting the valve cover and not the rocker body, though that might hit also. The cam companies sell shorter adjustable poly-lock nuts.
I use chrome-moly steel body roller rockers and they fit just fine under a stock rocker cover. They are as light as the aluminum rocker, and will not metal fatigue in the time the motor lasts. They are also stronger than aluminum rockers to withstand the high valve spring pressure of a solid lifter radical lift roller cam.
It you want another solution then you can go with a dual nine inch power booster, or a Hydraboost brake system off of a diesel van or light truck. New rockers are the cheaper of the two choices.