i read the link topic "
http://www.camaros.org/forum/index.php?topic=4291.0".
concerning 69z28 blocks I agree with John Z. as well as the others.
I also found an article in the Magazine Speed and Supercar dated April 1969.
There is an article titled Chevys Dynamite z-28 written by Martyn L. Schorr.
Within that article they discuss the components that make up the z-28.
One paragraph in particular mentions the block. The quote is,
'The 69 z-28 utilizes a new block with super-heavy-duty main bearing webs
which are cast oversize at the foundry and trimmed down for crank clearance
later'.
I'm not sure if they are just commenting on the three center 4 bolt main caps.
Comments welcomed.
asm69