<VV> Block #s, ain't we got fun!

[NicolCS at aol.com]

<snip>
My body Tag says 04D so I'm guessing I need T0421YR to T0507YR to be  in 
 the correct date range. But I could be wrong I'm still not completely clear  
on 
 the block code to body tag code relationship. <unsnip>

The block number always precedes the body assembly date so 507 is too late.  
I don't know about Corvairs, but in Corvettes the engine date is between -2 
days and about -5-6 weeks from body assembly date.  The engine cannot be made 
after it's put in the car  While Bob Helt's authoritative book decodes 04D as 
"forth week of April", 04D decodes to the fourth of November if Corvair dates 
are decoded like Corvettes.  In Corvettes, the body is one exception to the 
numbering scheme.  In 99% of the other date codes, A=January and L or M is 
December (some makers skip "I" (letter I looks too much like number 1).  Components 
follow this scheme EXCEPT for the body build where A= August!  (B=Sept,C=Oct, 
D=Nov).  IF Corvairs follow this thinking, you would want a block code up to 
TO1102 back to around TO1002 (two days before body assy to a month before body 
build.

I suggest that you research this fully and confirm the decoding of the body 
tag with a second or third authority before you select a block date.  I don't 
know why GM would use different body date schemes between lines and I am 
positive about the Corvette scheme.

Good luck and have fun!
Craig Nicol