Here's what I can tell you about my RB block. I should be getting it from the builder very soon. It went back last August due to a machining / core error in the oiling system. The oil port in the front of the block used to bypass an internal pickup intersected the oil pump drive shaft bore causing it to suck air. The only other issue I had was I ended up running a tall roller lifter due to the bronze bushings being tall.
What I can say is that Bill Mitchell was very helpful in getting my issues fixed with the oiling system and great to work with. My block was purchased in Jan 2017
Same problem here. I plugged the block and went to an external oiling system. I received this block over a year ago. I'd have to go back into the paperwork to figure out the exact number of months.
Also the oil passages through the block didn't line up and 9/16" diameter intersections were only 3/16" so I had to do a bunch of re-drilling.
The bronze lifter bushings were so out-of-round that by the time they were honed round they were too big. Fortunately the lifer bores in the block were round so I replaced the bushings and honed them correctly.
The block decking wasn't anywhere near lined up with the crank and cam tunnels.
The rear main oil seal bore was some weird size that no main seal on the planet would fit. Unless Bill Mitchell had something special tucked away.
Before the block arrived I was told on the phone, "Let us know what you think and how the block turned out."
I couldn't get Bill Mitchell to return my calls or emails. I was left completely on my own to fix the problems.
