I have gotten with some of the fuel racers and we have discussed main bearing problems as the HP and boost go up. I got an email from a known fuel racer in Nostalgia. This was his approach to better bearing life. Thought you might enjoy.
He writes:
We fought an oiling problem ,we now run .0065to.007on the mains with aluminium caps ,we changed 2 bearings in 2 years,
we used steel maincaps and they had a different growth rates -another problem ! Aluminium-aluminium-is best .
we use a titan oil. pump @120#billet fab oil pan -13 qts.
we use King bearings(easier to get .001 under or over localy)or C&A narrowed bearings ,
the priority oiling system used restrictors in the front-behind cam gear- and rear of the motor
check the cam bearing holes when the mains are out
.Where they machine the oil passages on the K/B olds they get thin at the bottom it can leak at that point ,
on the Arias block there is a little trough under the bearing upper half on each side of the main oil hole,we opened the oil holes up to 5/16 ,and drilled a 1/8 hole on each side of the main hole for more oil to the mains
we run Prolong every oil change
every third race we check the line hone ,as it seems to tighten up .001or so ,we just stay on top of it , we also stayed on top of the rods every once in a while we tighten up 1or 2 rods .001-.002 we just resize them at this point
we have had to step up our maitnence program ,bare frame every race ,but its cheaper than motors we have run 45 6.0 runs -no failures