Huh??  Frank, can you please explain?  In my book, restricting the flow at the existing 2 and 4 passages will have the same effect as blocking completely and creating new feed lines.  The main oil gallery flow and pressure would be the same in both cases.

Edit - Oh wait, I see it's a Top Oiler.  I still don't see any difference to the main bearing oil feed either way.  I could see how you'd think that taking extra oil at #2 and #4 would create a local pressure drop, but the flow is pretty minimal when properly restricted.  Taking the top end feed off the beginning of the main gallery would evenly distribute the pressure drop, but to me it doesn't seem to be worth the effort.

Interesting Scott!  I did not know this 

john-oldiron

Gapp-Roush was before my time there, but I never heard about any special things they did to their lower end structure on the 427 blocks.  I did get to know Ray Paquet.  He didn't do anything radical to the structure of his cross-bolted 427 blocks either (aside from rod journal diameter/width and oil system detailing).  The lightest possible reciprocating components and selecting for most consistent cylinder wall thickness were his focus on the block side.  There was a bit of block fill if I recall correctly, but that was mainly for cylinder wall stability.

Now as for general bottom end stability, nothing beats a bed plate.  That's where the caps are tied together into a massive plate structure that makes up the bottom half of the block.  It's pretty much a must-have for any modern max effort engine. Deep skirts with four or six bolts + cross bolting will get you a long way as well.  Those solutions will pretty much kill the bottom end wobbling that we were seeing.  You also want to lighten the reciprocating assembly as much as possible, and fully internally balance the engine.  We ended up building a "world class" four cylinder demonstration engine with a bed plate and all of the above tricks.  It was as good or better than anything out of Japan or Germany at the time.  Of course it never made it to production      As far as block fill, I have noticed some modern engines have shortened water jackets for improved structure.

I doubt you'd find a modern Formula One engine without a bed plate.  There are several production engines out there now that use them, especially if turbocharged.  At Ford, the Ecoboost V-6 Engine in the latest Ford GT, along with some Ecoboost four cylinders got bed plates.

Regarding cap and skirt movement...  While at Ford my specialty was NVH.  We were chasing improvements to engine sound quality by stiffening up the bottom end structure. 

Dyno tests with accelerometers mounted to caps and side skirts were eye-opening!  To say the stuff moves around, at stock power levels, is an understatement    I couldn't believe those results.  How does our stuff even stay together??

Two sets for me as well!  Thanks, Brent 

Like Ross, I'm guessing the spring pressure and installed height on that cylinder are just right for a resonance.  You can't rule out timing error due to the chain, but wouldn't you see that more on the exhaust valve?  I guess violent chain whip could cause the intake valve to advance enough at certain moments, especially if the starboard cam is installed really advanced...

I’m also finding that everybody thinks changing your oil every 7500 miles when the change oil light comes on is ok. I put 4000 miles on customers oil stickers even when using synthetic and personally I use synthetic and still change every 3000 or pretty close to it. I know oils are better but oil is also a cleaner and after 5000 miles or so I don’t think it’s better than regular oil at that mileage. JMO.

THIS!!!  Everybody seems to be on the extended oil change wagon these days.  Combine this trend with more power from turbocharging / direct injection and you've got rod bearing failures across several manufacturers.  Today's thin oil is not helping either.  Smart people are changing their oil more often, and evidence suggests they are experiencing far fewer problems.