340 with old Harland S rockers geometry?

mullinax95 said
I guess if I was in your shoes I would install checker springs on a pair of valves... mark the tips of the valves with some type of marker and see where the "scrub width" is located on the valve. Then take note on the width of the sweep pattern on the valve tips.
This will let you know what's going on and will help Mike at B3 with a starting point.

I'm not a fan of needle bearings. I bought the PRW 1.6 stainless steel rockers in which they are bushed to fit the shafts. No needle bearings. When I received the PRW rockers I read the instructions before taking them out of the box. It spoke of needle bearings. I immediately took a rocker out to make sure they did not have needle bearings.:)

Needle bearings might me better than bushed ... I don't know...but my personal preference is not to run them. Small little part that is subject for failure. If you have been running them since 1975 without problems .... just disregard every word I have said.:D

Problem is the needle bearings wear the races out, the race ride on the shafts after that and get a little noisier and then it forks the road right there depending on the shafts used "induction hardened" "hard chromed" etc...2 things now, the guys setting them up don't space them tight... .010...and so "A" races go away and needle bearings get loose through huge side clearances or "B", the shafts go bye bye and all that debris takes out the bearings and oil pump. Thing with MOST but not all, needle bearings rocker arms, is that they have a limited life span and people misrepresent that as destined for failure. It's the same as tires, milk, meat...you
Something to remember also is most parts failures are user related, not design...or not beyond lifespan or cycle usage . Just like a tooth brush....you gotta replace it ever so often. If given a choice I'd take the bushed or steel bore over a needle bearings on the street because then it's something I'd worry about less...but if I were competing I wouldn't shy from using the needle bearing rockers because they lighter n theoretically run cooler, less surface area contact and moslty I would be on top of that motor like flys on **** to check them.