Any one interested in the oiling mods I did?

Duane said
I think the thing to remember with all these mods is that the recommendations coming from Chrysler or the Larry Atherton book are not to be looked at individually. They are recommended for extreme applications. They are not recommended as to say lets do just this one. They are recommended as an all or nothing because they are interrelated. I have had this oiling discussion many times in the past and there are always non believers of this part or that.
I fail to see why anyone would question Chrysler. They have cast the r3 block with no oiling to the lifters because it was designed as a race block. A race blocks needs it oil path restricted because of the intended usage.
The sbm is not a new engine design. Many racers before us have raced it and can tell you about its oiling issues and how they got it to work. Sanborn was a very successful sbm racer who shared in much detail how he got the engine to live. He too was an engineer.
I had Cometic gaskets design Mls head gaskets for the sbm with the water passages modified to Sanborns design. Anyone on this forum can now buy them. The main bearing problems with sbm are very well documented as are the fixes. But some guys want to do there own thing. To each his own. But my own personal experience with my own engines is that tubing the block and opening the passages works. Restricting the cam bearings works, Reading the article you referenced has confirmed what I thought. Rod bearings oil from centrifugal force, viewing the rod oiling from that perspective makes me realize that opening the main passages to 5/16 and slotting the bearing shells increases the dwell time to get oil into the crank passages.
The higher the rpm, the less time To get it in there. Those passages do not just feed the main bearings, and when the crank passage needs oil, you need to get it there quick.Opening any passage is the easiest way to improve flow and reduce pumping losses.

Agreed - individual mods don't do squat. The mods are intended to reconfigure stock system to a racing system and are not intended to address specific shortcomings in any one area.

That's some of what's causing disagreement though, is that some steps are being discussed in isolation, and the reasoning invented to explain the steps just isn't accurate - even if it's a 'good' step to take toward reconfiguration, but no single step does much good (except for using a larger pickup and opening ALL the passages associated with the pump and filter - those should be made yuuuuuuge with respect to cross sectional area).

Just drilling the mains feeds larger is likely to cause more problems than gains. But do it AND block the cam feeds (restrict) and you've likely helped balance flow to some extent. Restricting feed at the #1 to the opposite lifter bank goes along with that.

But none of theses steps or reconfigurations is done to eliminate velocity. They're done to eliminate leaks PRIOR to feeding the mains. By doing so, the pressure available to the mains is retained and only drops after them, not before. That's basically what all the racing blocks did - they feed the mains first, the mains feed the cam, and the lifters are fed from the last cam feed. That last cam feed determines the flow potential to everything that's not a main bearing, and so chances for catastrophic oil pressure loss at the mains is reduced.