833 belhousing adapter ring

Why doesn't anyone make a adapter ring to go from a regular 833 4 spd with the 4.35 dia. bering retainer to the 5.125 O.D. bell housing? I'd like to put a non O.D. 4 speed behind my 71 slant. I can find O.D. bell housings all day for the slant but no regular 4 speed ones. Anyone on here with a lathe interested in turning out a few?
BTW.
Why are you contemplating this gearbox change?
I have run every Mopar gear ratio there is, and for a slanty, the OD box is a pretty good DD choice. Just not with hiway gears. The OD box likes 3.91s With those, your Road gears would be-
12.08-6.53-3.91-2.85 The gear of note in this box is Second gear; 6.53 will get you from 30mph@2500 to 60mph@5000.
If you want a 6.53 with the standard box, you would need a 3.40 rear gear to hit it in Second, or a 4.66 to hit it in Third.
now whereas the the Hiway gear with the od is 2.85. the hiway with the standard box is 3.40 which is 19.2% more hiway rpm. And
Whereas the starter gear with the od is 12.08, the standard offers only 8.84 with a 3.40 gear.
So the, the ONLY advantage to have the standard is to get an in-between roadgear to reduce your rpm when cruising at say 45 mph. But you have to sacrifice BOTH the starter gear and the cruise-Economy.

On the other hand,
A starter gear of 10.0 with the Overdrive requires a rear gear of just 3.23, which will get you a cruising gear of 2.36 which will get you 65= about 1950 rpm. If you optimize the Ignition timing and AFR for that, then you'd be looking at really great hiway fuel economy.

I know for me, if I had a Heavy-A, (73 up) with a slanty, set up for a manual trans, Then
the A833od would be my first choice, but Ima thinking with 3.91s.
Or, with a 67 to 72 A-body, maybe 3.73s at the least.

Having run that od box for several years, I know the 1-2 shift drop is pretty wide. By running an appropriate rear gear, this can be alleviated and then Second gear becomes a lotta fun. A second gear overall ratio of
1.67 x 3.91= 6.53 is a lotta fun.
I currently run 6.82, which is only 4% better, and I love it. Allbeit I have a Hot 367, lol.

Just trying to be helpful.