hydraulic lifters or oil pump

[58pan]

have a 58 pan that I rebuilt and it seems like a new engine when it starts but when it gets warmed up I can hear the lifters making a lot of racket I didn't check the lifter blocks to good and was wondering if that could be the problem or would it be the oil pump?

[cdndewey]

Did you install the lifters correctly? The holes/flat sides have to be on the inside facing each other.

[T. Cotten]

58Pan!

Can we assume you have OEM-style hydraulic lifters and OEM cam?

....Cotten

[58pan]

not sure I did it was 8 years ago but I did check the oil pressure and it was 18 at idle and ended up puting solids in for now but thanks for the info