Tuning the MP 360/390hp

What's that cam, the 292/508 roller? If it is, do 24 initial and the rest mechanical if you want some advance curve in it. If it starts locked out when hot, I'd run it there. You could test it doing the vacuum gauge method, Only change is wherever it make most vacuum, lock it down there, no backing it off because it starts beyond your total number.

There's a thread on here with the window widths for setting mechanical with those mallory style units. Don't need the keys, use an appropriately sized drill bit shank!

The curve itself may not be right but the initial/mechincal will be in the right area.