Very easy to turn up with right injectors ,well tuned rack ,limiting speed governor instead of torque limiting , fuel pressure increase . They make a fluid dampner for them factory part . Run the cam timing one tooth advance instead of straight up has marks for both . Make sure it has 100% blower instead of 80% . Both look same externally just one has thinner housing and larger lobes . But real power is in the turbo, blower is there for scavanging. By the valve cover shape I would say it has four valve heads instead of older two valve heads . And really rare and damn near impossible to find is the few the military aluminum blocks . There is also 8v53 out there as well will rev a little higher than the 72 series but they tend to be hard on cranks .