I had an interference problem between some of the exhaust retainers and the self guiding pieces of the roller rockers. The springs were cc 986 with 10 degree locks, rockers are LT4 and valves are Federal Mogul.
I changed the springs to crane 308 and the problem is still there. So now I think it’s the valves, I think the locks groove is placed higher on these valves. These are supposed to be stock replacement small block valves, did they come with different groove height, am I better of replacing the locks with offset ones like -0.05” installed height.
Thanks

 

I have read somewhere that (GM) LT4 roller rockers would only clear up to .550 lift. The XE 230/236 cam has .555 lift at the exhaust, that definetely would explain your problem.

 

This issue is with my B-car, it has a crane 227 cam with 0.553 exhaust lift. The LT4 rockers are actually good for 0.575 and that is limited by the slot not the tip. These same rocker were working fine on my F-car before I changed to nsa promags.
I want to make sure what I need before tearing up the motor.

 

I had a simular problem with my 190cc AFR heads and the GM rollers. The rocker body rode on the retainer and not the valve. Causing undue wear on the rocker. Come to find out the valves were too short by .010. Had to use the narrow body CC Pro Mags and no further problems. I hope this helps.
HVY SS

 

Thanks it did help, better to change the rockers then to tear up the motor. Are these self aligning rockers?

 

Yes. When you order them make sure to tell them you want self alining rockers. Summit and Jegs both stock them.
HVY SS