Phosphor Bronze lifter bores

[CobraEd]

I found this little article on the "Hot Rod" web site:

Lifter Bores

Lifter-bore problems are rare because most engine designs provide plenty of pressurized oil to prevent excessive wear. When a used block has seen service in a racing application, some engine builders enlarge the lifter bores and install bronze bushings to restrict the flow of oil to the valvetrain so that more of it gets to the crankshaft. This practice is viable in certain racing applications, but on the street it often causes rapid valvetrain wear. If you spot bronze bushings in the lifter bores of a used block, move to the next candidate.

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