I've been playing with Hemis for 30+ yrs but never a tru "Race" hemi as in a '64 or '68 "Race Hemi" That being said I have never seen or heard (maybe forgotten) about a different damper, timing cover or keyway location that would prevent the use of a different TDC location on a damper from one motor (Race vs Street) to another. This is brought about due to a question posted on FB showing an aftermarket Damper with a Street Hemi TDC and a Race Hemi TDC inscribed from the mfg about 8degs apart. What have I forgotten??

I believe the race Hemi motors used the narrow wedge type dampeners in both the 196/65 race hemi and the same in 1968 on the race hemi motors only.
Mopar change the timing covers and the dampeners in for 1966 and above for emissions is what we where told in one of the old drag racing seminars before 1980. The zero mark on the early timing covers is at to the top and they are in the middle on the later ones, the timing line on the dampeners are around 10 degree different also.
It can be confusing if you don't verify TDC when assembling the motors, especially if you have both early and late parts

Its more of a curiosity question than a "I have a problem" question. I have never used a stock damper or cover even on the early Iron block stuff.
Update... guess I figured I'd put some effort into this and broke out one of my old Direct Connection Engine Manuals and found the following