Thanks for the info. I just purchased these. I may be able to get them on without moving the exhaust because of slanted side, hopefully

Hi, My engine shop guy came over and checked the geometry of my valves, pushrods and new rockers. Marked the top of valve stems with a sharpie. Set zero lash on cylinder #1 intake and exhaust. turned 1/2 turn more.. Turned over engine several times. Removed rockers and he said where the marks are I am fine leaving it there. No need to change the pushrods. see attached photos. I started both engines up without the valve covers oil was getting to all rockers and best of all no clicking noise after shut down. Apparently it was the old rockers and balls. I don't know what spring pressures they are rated for but it must have been borderline because some of the old stamped steel rockers started to change color. Thanks for all of your help!

Fixed

Sweet!

Nice thread, a lot of good information came from a lot of people, ultimately you were able to achieve the desired results...WIN!

Just found this info....Maybe the cause of my rockers going bad and changing color

Many circle track racing classes require stamped steel rockers. Maximum lift and valve spring pressure are the two biggest limitations. A good rule of thumb is that you shouldn't exceed 0.500-inch lift and 350 pounds of open pressure with stamped rockers.

That quote is for small blocks.^^^

Added info:
Zz502.uses 1.7 stamped rockers. It has .527” .544” lift. It uses a dual spring with 325lbs per inch rate.
uses this spring: https://www.summitracing.com/parts/nal-12462970

well my lift is.531 and .551 with dual spring plus damper and lbs ?? must be over 350... If I am getting oil then the stress of the lift/lbs pressure was wiping out my rockers for years.
Well i'm glad that's over
I would have went the roller rocker route years ago but I like the ability of being able to remove my valve covers without removing the exhaust. I found these covers...Its tight getting to the 4 lower screws by the exhaust but its doable

Sounds like you have a 420/525sc cam (Crane 132561 or 139241) or a similar clone.
These would be the Crane recommended springs for those cams https://www.summitracing.com/parts/crn-99839-16

Yes

Brand: Crane Cams
Manufacturer's Part Number: 132561
Part Type: Camshafts
Product Line: Crane Hydraulic Flat Tappet Camshafts
Summit Racing Part Number: CRN-132561
UPC: 021174039900
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 2,800-5,800
Intake Duration at 050 inch Lift: 228
Exhaust Duration at 050 inch Lift: 236
Duration at 050 inch Lift: 228 int./236 exh.
Advertised Intake Duration: 298
Advertised Exhaust Duration: 306
Advertised Duration: 298 int./306 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.530 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.551 in.
Valve Lift with Factory Rocker Arm Ratio: 0.530 int./0.551 exh.
Lobe Separation (degrees): 114
Computer-Controlled Compatible: No
Grind Number: H-228/312-2S-14 T1.2
Valve Springs Required: Yes