'69 bell housing bolts

[rlw68]

I've heard the early '69s bell housing bolts had an 'M' marking.  These supposedly changed to 'A' marked ones at some point.  Anyone know roughly when this occurred? 

Rob

[bertfam]

Rob, bolts, nuts, washers, and all fasteners in general were supplied by several vendors and all of the same size were mixed in together in the same bin. There's not "A" correct bolt for a given application because the line worker just grabbed whatever was in the bin and used it. You'll see all kinds of markings on bolts from nothing at all, to letters, to symbols.

Ed

[rlw68]

Thanks for the reply Ed.  Yes I get it they could've had a bin full of RBWs on 2/28/1969.  Who knows
AMK has been my goto for an 'acceptable' replacement when needed.  However in this case there are two bell housing bolts to choose from for 69.  It seems very specific.  Either way whats in there now aint even flange bolts.

G-6611    BELL HOUSING>ENGINE   FLNG BOLTS, "M" MARKING   
G-6149    BELL HOUSING>ENGINE   FLNG BOLTS (Flat Top) "A" MARKING   

[Mike S]

 Buy a bag of each.....it would look just as 'correct' mixed as it would not mixed.

Mike

[ko-lek-tor]

The “A” head are flat across the top, whereas the “M” has a recessed top. I was under the impression that although they are the same length bolt, the “A” was for the aluminum intake 396-427 engines (possibly 302, not sure)?