<VV> (no subject)

[BobHelt at aol.com]

Hi Mark,
Apparently you are not aware of the story, so here is a  reasonable repeat 
of what happened.
 
In About April 1962, the Tonawanda engine assembly plant  discovered that 
their bearing supplier had supplied some #1 main bearings with  "mis-matched 
flange" thicknesses. So production engineering studied the  situation and 
found that those bearing couldn't be used as is, BUT production  had to 
continue. So they issued a Tech Bulletin stating that only one half of  the 
flanged bearing would be used and the other half would be the same as the #2  and 
#3 main bearings. Thus, production continued until the supplier could supply 
 the correct #1 bearings.This correction happened toward the end of  1962.
 
But unfortunately, this problem and the solution got  announced to the 
bearing industry manufacturers and suppliers. So the  bearing industry started 
manufacturing replacement bearings with this  combination of half flanged #1. 
The whole industry converted. And they NEVER  went back to the original 
configuration. But Chevrolet DID. So there are STILL  many main #1s being made 
and sold with the half-flange.
 
The good news is that the half-flange works perfectly well. It  just looks 
strange.
 
HTH
Regards,
Bob Helt
 
 
 
 
 I fully intend to check the clearances using
full  flanged bearings. 
Brian, that is all you can do. Maybe some blocks were machined  differently
for some reason and they did the half flange to prevent it from  being too
tight. Do check for that, my engine was at the inner limit with two  flanged
halves in there.