4.050" is the spec given in the old MP engine book to make it so you can use w2 rocker stands on std heads.
Looks like that's what was done to those heads.

It appears they milled the valve cover rail as well.

"In theory", you would need the w2 rocker stands(P5249049)and offset shafts(P4120589) to fit those heads, if they have the std length w2 valves.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads