Did you by some chance get lifters or pushrods for a 67 440??
They changed in 68 and can be used in an older block, but you cannot mix n match the old lifters or pushrods with the newer stuff.
I know WAY out in left field but??????
I don't think that would be an issue, companies stop making that small cup lifter decades ago.
Nope..... Still available. Comp cams 824-16 Hylift Johnson A-812
Probably some others as well
Thanks for the clarification, really surprised they are available .
But I think that the only difference is the ball and plunger cup size. I think plunger height and PR length are the same. I guess if you put a 68 PR in a 67 lifter the total stack height might be a little more.