I was browsing the web and found a company that supplies crate 223 engines; they supply the aviation industry. Apparently the motors are in a lot of the ground support vehicles at airports. I'm sure there are plenty of 300's in them too. I did find some info on the top end oiling problems. Most of it was due to improper bearing assembly, and/or the lack of detergents in the old oil. The oil passages in the head are small and they would get clogged with sludge. I will wait until the motor is all together and make sure that the oil is flowing properly through the rocker arm shaft. One thing that intrigues me is the posts I have found where people claim 17-20 miles per gallon on the highway. For someone with a couple 460 engines, that sounds AMAZING!
What's the company's name?
17-20 mpg matches the EPA ratings for Ford Econoline vans in the 80s with the 4.9L (300) and the various overdrive manual transmissions offered. These engines made 145 net hp and 265 net lb-ft. I have 2 such vans, one 5 speed OD and one with the C6 auto. The 300 is renowned for its longevity and low-end power. With stock 29" tires, stock gearing, an automatic and at GVWR, it's adequate, nothing more. I mention that because your 223 was rated at a maximum of 145 gross hp and 206 gross lb-ft. in certain truck applications. Note that these ratings differ from those for the 300, in that they are gross, not net ratings. The 223 numbers come from a bare engine with no accessories, no mufflers, nothing. The 300 numbers are from a fully dressed engine with full belt drive, all emissions equipment, full exhaust, etc. Two totally different sets of numbers that almost defy comparison. Even so, I would not wish to lose even a single digit from my bigger, more modern, fuel-injected engine which is both more powerful and has less work to do than yours.
I really enjoy your thread and look forward to more I-6 goodness.