are you talking 3 inch diameter 1/4 inch reel to reel?
....because 3 inch width tape isn’t a thing

2 inch....different story...
No, Sir, that's 3 inch width magnetic tape on a 7 inch reel...
It's a very interesting story...and keep in mind that Mom was a personal friend of Buck and we spent a lot of time down there.
When Buck renovated the old River Movie Thetare at 1213 North Chester Avenue in Oildale, California, in 1968, they used a modified Ampex 300 console, modified by Grover Harned. This was one of a handful of prototypes, converted to use 2" wide tape. These devices would evolve into the MCI JH-24. Along about 1972, the studio upgraded to an MCI JH-400 and again in 1975 a MCI JH-500 was installed.
Buck was interested in going beyond 24 tracks, but in order to do it, a wider tape head and tape would be required. The only way - at the time - to record 32 tracks was to use 3" wide tape. Only one company made that device, and that was MCI. Only one company - 3M - made the 3" wide tape fitted to 7" reels. Grover Harned installed the prototype 32 track, analog deck at Buck's studio in early 1978, and it was used up until the studio closed in 1992, although the studio 'officially' went digital sometime around 1981.
This comes from Mom's legal pad notes from the 1978 sessions. We also "borrowed" David Frizzell's drummer, the late Bobby Gallardo, for this session, who was "on loan" to Merle Haggard at the time.
So all of the songs, from Mom's 1978 summer session, were recorded on 3" wide masters. Mom has these original masters in storage at The Ranch Studio, but nobody (that we have yet found) is able to fit the rare 3" wide masters to be able to pull the tracks off of them.
Photos taken during Mom's 1978 Summer Recording Session:
Producer Jim Shaw listens to a playback in the control room at Buck's Studio - July 1978
Mom (in red/white checkerboard) at the console flanked by Shaw
Buckaroos Don Lee (Standing) and Terry Christopherson enjoying Big Macs
with a smaller reel-to-reel behind them, likely a Sony.
The big 3 inch MCI console was to Terry's left
Terry and Me during the July, 1978 Summer Session.
Here is one of the few songs from that session that was later converted to a 2 inch wide master.
My oldest Son converted it to digital and uploaded it to You Tube.
The deep, baritone voice singing backup is Don Lee: