Howard’s Allison Conversions makes adapters that use the Dodge Cummins adapters on the engine side, which are preferable for most swappers that have compound turbos, because they retain the Dodge starter on the driver side of the engine. They are only compatible with the SAE 3 Allison bellhousing, which can be interchanged with the Chevy bellhousing. This adapter setup requires the most parts but still is competitive in cost with the Chevy adapters.
One of the things I like about the SAE housings is the cooler connections are on the bottom of the bellhousing, so they don’t get tangled up with your exhaust.
Be sure to tell Howard exactly what Cummins you have, there are differences in the thickness of the various adapters that were used on the Cummins engines through the years.