[b-man]

Originally Posted by pmd400

With an iron headed 9.5:1 455, what is the cut off point where roads lifters would be beneficial. With a 068 cam I assume rhoads wouldn't be needed. What about a summit 2802 or crower 60243 cam?

I wouldn't use Rhoads lifters with any of those cams in a 455, and especially not with the 068 in any size engine. Using Rhoades lifters would invite detonation by building cylinder pressure too early. The 455 can easily handle those cams and still have plenty of low-end grunt without using variable-duration lifters.

Once you step up to the RAIV cam or something bigger I'd start thinking about using them in a 455.