Dear Rob;

We had lifter failure on the Hot Rod six(s) (Chevy & GMC) in the 50s, long before this oil controversy.

Also I have used Dello (a diesel/commercial) oil for decades with better than 'normal' results.

Anyway; the major cause of lifter failure was the double springs needed for 'high' RPM use back then. We used to check the lifters on a regular basis, usually when the valves needed adjustment etc. Replacing the bad ones solved the problem and the cam.

Today with the "new oils" It's worse, is all. The public has been sold on multi-grade which is NG for the early/Hot Rod engines.

The secret is to use the Howard springs (single) which are strong enough to NOT 'float' the valves, but doesn't put excessive pressures on the lifter/cam interaction(s). This along with Dello or the Castrol product you mentioned "does the trick". \:D

Thanks for doing the research here as this has been an uneeded debate on our BB for quite some time.

Good luck to all. \:\)

PS: Patrick's has these springs.

John M., I.I. #3370

"There are no shortcuts to any place worth going". -Anon