Brian that old Cam Dynamics 275 @ .050 is almost a exact replica of the MP 590 It does have 3* more duration @ .050. It will run just the same as the 590, maybe just a touch faster because of the extra duration.

A member here once swapped out the mp 590 for a Comp cam 274/282 @.050 .590/.609 on a 108 LSA and didnt see any realistic gains, even though the cam was bigger and had more lift. The LSA was more spread by 2* but overall same Et.

I agree with you on using that old Cam Dynamics cam. To measure a cams duration you need to measure it with a degree wheel.