cam upgrade to crate motor

the power band is ok i guess. what im really wanting is more power. the cam thats in the engine now just seems like old technology. its only a 513 lift. the valve springs are good to 560 and in another one of my magnum engines im running 1.7 rockers same cam but total lift comes out to around 550. so i know theres more room for air flow

The cam lift and rocker ratio has zero to do with how much a head can flow. That's all in the size and shape of the ports, bowls and valve sizes.