I measured a 109 @ 2.030It's a bit of a head scratcher. It appears to have all the same traits of the 153 blocks. It seems to me there were some On Center blocks made that had a raised cam tunnel. I have never seen one personally, I believe Prasad had one at some point. Can you take a rough measurement between the main bearing bore to the cam bearing bore?
I had 6 unfinished BMS cranks that I took to Kings and had them finished.He mentioned that GM had cast 50 blocks but he wasn't sure they'd take time to machine them because they didn't feel the demand was there
Ok, getting a idea on these, thanks Neal for your info.I'm not sure I have any more ideas on Bill's specific block other than it would have to be one of the last On Center blocks cast as the casting # is numerically higher than the 153 block.
I do remember having a discussion with Kenny D back in the day circa 1995 about Stage 2 blocks and their availability. He mentioned that GM had cast 50 blocks but he wasn't sure they'd take time to machine them because they didn't feel the demand was there. Maybe this one of the last group?
As a question is there a U followed by 4 digits stamped into the forward face of the block? These numbers are sequential and should give insight into when it was machined. There was a whole discussion on this at some point but I can't find the thread.