Quote:

---

The oil pressure changes a lot with aluminum caps too. Not a major problem with aluminum rods because they are the last in the oil sequence, but mains need to maintain their clearance. Also, it's much harder to line hone with aluminum caps on an iron block since the caps cut quicker. You can make anything work but is it worth the effort? Most machinists would stay with what they know.

---

Rich, That's the first time i've heard anyone say anything about fluctuating oil pressure when using aluminum caps. I've installed close to a hundred sets over the years and have never had such an issue.
I always align bore the block when installing any cap conversion whether it's steel or aluminum. IMO that's the proper way to do it. some shops will bore the mains to within .001 and hone the rest, which is okay as well.
I believe the aluminum caps help dampen harmonics to some degree. In any case, I think it's been a time tested upgrade to help our stock block combo's live a bit longer when pushed beyond their normal limits.