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I have heard many times that it's best to use the lifters that the cam manufactrer recommends because, for one reason, the curve of the lifter bottom has to match the taper of the lobes. Is that an old wives tale?
Cam lobes are manufactured with a FLAT, but tapered surface.
The taper is to make the came move REWARDS as lifters contact it.
There is NO 'Dome' or 'Concave' profile to the camshaft lobes since they are Ground & Polished on a flat grinding stone and with flat belts.
The slightly higher rear side to the camshaft lobe taper will move the camshaft to the rear of the engine when the camshaft is in operation, meaning you normally don't need a 'Cam Button' or 'Anti Walk Limiter' with most modern flat face lifters. (Mushroom shaped solid 'Flat Tappets', Mushroom shaped Hydraulic lifters, or regular straight cased hydraulic or solid lifters)
Most lifters are SLIGHTLY DOMED when they start out, and will wear concave as they wear out against the camshaft lobes.
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Lobes on ROLLER TAPPET CAMS have to be completely Horizontal with the camshaft bores, and the tappet bores have to be exactly perpendicular to the camshaft bores so the rollers ride smoothly on the camshaft lobes.
This requires an 'Anti-Walk' button, or camshaft movement limiter to keep the camshaft from walking forwards and trying to get out of the camshaft bores during operation.
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Myscrambler1 is ABSLOUTELY CORRECT,
Anytime you put in a new camshaft, you should ALWAYS use new lifters,
And the lifters should ALWAYS remain on the same lobes of the camshaft!
NEVER, EVER mix and match lifters in a block or on the camshaft!
The liftes get specific wear patterns to both the camshaft, and to the bore they ride in, and you simply shouldn't play 'Mix & Match' with those wear patterns!
If you have a lifter that quits...
This would be the ONLY exception to the rule.
And when you put a new lifter on a used camshaft,
Make sure you treat the new lifter and camshaft lobe like they were BRAND NEW...
Use the correct lube, Go through the correct break-in procedures, ect.
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What most people don't realize is the pushrods, rockers, ect. develop wear patterns on BOTH ends,
And the rocker arms develop wear patterns on BOTH ends,
and in the case of the 'Shoe' type rocker arms,
The 'Shoe' fulcrum develops wear patterns with the rocker, so they should ALWAYS be removed as assemblies, kept together, and put back where they came from if you need to do head removal or repairs to the engine.