This engine has done this through two sets of cyl heads. When I swapped heads I checked all the pushrods, rockers, etc..
When I pulled the intake this last time to reseal it again, I inspected each one and all looked good.
79 Cherokee Chief 401/T18/D20, MPFI fuel injection, hydroboost, otherwise stock.
Future mods: Caddy 500/NV4500/NP205, HP D60 front D60 smooth botom rear, 5.13 gears, 35x12.50's on H1 beadlock wheels. Warn M12000 winch.
93 Wrangler 4.6 stroker/AX15/NP231,SYE,CV, OME 2.5 lift, front hub conversion/big brakes, 31X10.50's Warn M10000 winch.