I thot it was always better to replace the cam and lifters together as they both create a wear pattern

no offense at all. theres a lot of people out there that overlook a good complete strong valvetrain setup.  and yes they're EXTREEEEMELY costly when you price the whole thing.  i have a tick right now that i want to address.  if i can upgrade a few parts while replacing the broken ones (i think its a lifter) while keeping the parts that are in good working order (pushrods, springs, valves, etc...)

Had a "tick" in one valve/lifter, all stock 454, ('78 k30 4x4 wrecker) #2 cyl, first lifter, Exhaust, I think. Replaced one lifter without pulling the intake, kind of a bitch, and lasted another 4 years ~80,000 mi. (Lower end finally got loose, 'Rattled' at idle.) these were 781 heads, and enough room to sneak a lifter through the head and into the lifter bore, several pushrods removed. Had I dropped it, I would have (had to) taken the intake off. One of those quick fixes that lasted till the rest wore out. These trucks HAD to be running and reliable at all times, it was 24 hr towing/recovery.

Try running the valves first to find it, then see if you can sneek one lifter in, all else fails, pull manifold and put only one lifter in, or bite the bullet and do a cam/lifter kit. After I went roller, I'd never use a flat tappet again, unless I had to--racing rules, oddball engine, etc

Marvel mystery oil works wonders too

Thats all I got

Daniel