JUST REPLACED THE CLUTCH, ETC, AND WHILE IT WAS DOWN, LOOKED FOR THE "CODE NUMBERS" ON THE TRANNY CASE.
ACCORDING TO THE NCRS BOOK FOR A '68, I HAVE A MUNCIE HD 4 SPEED, 1968, JUNE 12TH, AND NO "SUFFIX" NUMBER FOR THE GEAR RATIO, WIDE, CLOSE, ETC. SO.....NOW WHERE DO I GO TO FIGURE IT OUT? ANY IDEAS???

Off the top of my head, HD 4spd would be the M-22 close ratio.

I think it's likely to be an M-21 close ratio. I think the M-22's (or "Rock Crusher") trannies were meant for L88's and the super high HP engines. It's possible they may have been been optional for the others. My '69 L71 427/435 has the original M-21 close ratio which was standard for it.

I believe most wide ratio 4-speeds were the M-20, and most close ratio's were the M-21, but I have heard of close ratio M-20's and wide ratio M-21's.

If it has fine splines it is a HD (AKA Rockcrusher) 2:20 to 1 -
if coarse splines with a ring machined in the middle of the splines
it is a 2:56 (Wide Ratio)
Or a coarse with out a ring is a std duty 2:20 close R.