I would use either the 408-6 or the 400-6, depends on what he wants, many builds have been done with the 408 The 400-6 cam is a torque cam, it will carry the torque out to around 5000 rpms , and if the heads are right they will carry the h.p. out I use a 400-6 cam Its carries a very flat trq out to 48000, I have 110 ftlbs at 2800. A 120 should do better due to the increase in cubes, All depends on what he wants. a 408-6 woods is a very good wind em out cam also!!!!!!! , He may love it , But personally id use the 400-6 It will out "torque" the tman cam 600 sm easily again tuned correctly
Timkens ?? eh maybe way to many big builds already getting no timkens and surviving well, Using the 2 Black upgraded S.E. roller bearings and very happy, The most important thing there is crank alignment to increase survivability and plugged/welded , The S.E. rollers are a little more forgiving, But very strong also
And actually the stock, 96, 103, 110 crank isnt cast, It's cold forged!!!!!
Heads?

?? Hillside cycle of course