I remember reading about that, from the Chipletter in 2022[0]:
"The XT/370, with a hard drive, could be purchased for as little as $8085. This compares with a basic PC/XT with 256K RAM for $4395 and adds a lot more functionality."
...
"So what was the PC XT/370? Put simply, it was a PC XT (the original IBM PC with a hard disk drive) with three additional cards:
PC/370-P : A card with one modified 68000, one standard 68000 and lots of logic chips.
PC/370-M : A card with 512 kilobytes of memory.
PC/370 EM: Providing the ability to emulate an IBM 3270 terminal.
The XT/370 then became three machines in one:
An IBM PC/XT.
An IBM 3270 terminal that could be used to access a System/370 mainframe.
A machine capable of running some System/370 software."
"The XT/370, with a hard drive, could be purchased for as little as $8085. This compares with a basic PC/XT with 256K RAM for $4395 and adds a lot more functionality."
...
"So what was the PC XT/370? Put simply, it was a PC XT (the original IBM PC with a hard disk drive) with three additional cards:
PC/370-P : A card with one modified 68000, one standard 68000 and lots of logic chips.
PC/370-M : A card with 512 kilobytes of memory.
PC/370 EM: Providing the ability to emulate an IBM 3270 terminal.
The XT/370 then became three machines in one:
An IBM PC/XT.
An IBM 3270 terminal that could be used to access a System/370 mainframe.
A machine capable of running some System/370 software."
[0] https://thechipletter.substack.com/p/motorola-intel-ibm-make...