I do not all Mitsubishi engines in CAT, but I know that Caterpillar 320, 320L 8LK series use Mitsubishi engine (the Model is 3066 but it is Mitsubishi engine, our company spare parts for it, the parts had a Mitsubishi sticker).
With looking in Baldwin filters catalog I found many Mitsubishi engine inside CAT equipments, this is the list:
CATERPILLAR 307, Serial N°: 2PM1-UP / Mitsubishi Engine 4D32
CATERPILLAR 307 B & C, Serial N°: 4RW1-UP, 5CW1-UP, 6KZ1-UP, 7DZ1-UP, AFB1-UP / Mitsubishi Engine 4M40
CATERPILLAR E110, Serial N°: 3FG1-UP / Mitsubishi Engine 4D31-T
CATERPILLAR E110 B, Serial N°: 8MF1-UP / Mitsubishi Engine S4K-T
CATERPILLAR E120, Serial N°: 1LF1-UP / Mitsubishi Engine 6D14
CATERPILLAR E120 B, Serial N°: 6JF1-UP / Mitsubishi Engine S4K-T
CATERPILLAR E140, Serial N°: 1NF09041-UP / Mitsubishi Engine 6D14
CATERPILLAR E200 B, Serial N°: 6KF00234-UP / Mitsubishi Engine S6KT
CATERPILLAR E450, Serial N°: 3HG1-UP / Mitsubishi Engine 6D22-TC
CATERPILLAR E650, Serial N°: 3KG1-UP / Mitsubishi Engine S6B-TA
CATERPILLAR E70,Serial N°: 3BG1-UP / Mitsubishi Engine 4D31
CATERPILLAR E70 B, Serial N°: 5TG1-UP/ Mitsubishi Engine 4D32
CATERPILLAR EL200 B, Serial N°: 6KF1-00233 / Mitsubishi Engine S6KT