the stock cam is kind of ridiculously bad. not so much if you consider the stock port size, geometry, and manifolds plus the early t3 turbine but once you remove those restrictions it becomes a major limiter. the stock lift is something like .313/.325 with duration @ somewhere around 230*. the rockers are almost the worst part of the problem i will give them credit the carbide facing with the hardened cam solved a lot of issues with that set up but the stock ratio is 1.05:1 with no real room to improve that or even integrate a roller element to allow for bigger/more aggressive ramps.

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1985 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
KD9AFT
A&P