New cam issues,

hey guys forgive my ignorance, my buddy just gave me 16 small block oem lifters that were used, he had them awhile and cant remember where they came from. Here is my question, are all small block hydraulic lifters the same? Im talkin about 318 and 340 lifters are they interchangable? same size,height and width?
These are a matching set just not sure what engine they came out of.
I will be sending these to Oregon cam for re-surfacing...Thanks for any info and advice...Rich

All hyd or solid small block lifters are the same dimentionally. The only outliers are the roller lifters and you won't have to concern your self with those. An excellent primer is the HP Book How To Rebuild Your Small-Block Mopar by Don Taylor & Larry Hofer (HP Books - 83). It should give you answers to most basic questions. Get a copy, read it, then come here for more in depth answers. Working with Ken at OCG is also a smart move on your part. Let us know how things go.