Groove in rear cam bearing on 66-67 396 engines

[retengw31]

Hoping someone here is familiar with this one, good friend just finished up his 40 Chev Street Rod from the gound up. He rebuilt the 66 396 engine with a Crane Cam, everything came out fine, runs great. Except when he was cleaning up some paperwork, he came across a thing in the cam box that said if you use that cam on a 1966 or 1967 396, the rear cam bearing needed to be grooved on the camshaft before you put it in. He checked the old removed cam and sure enough it was grooved.

He's worried he has to tear down the whole front end of the car to pull the cam on this, and that's no easy task. It's a typical loaded street rod with A/C, rack and pinion steering, etc. and the entire front end will have to come off.

Anyone familiar with this? Is it really necessary to machine this groove in a new cam? Never heard of a big company selling a product like this that would require machine shop work prior to installation.

Anyone know why a newer 396 wouldn't need this groove? Appreciate all hints.

Thanks,

Dave