Cm870 ecm

[Rawze]

Personally, in the case of a CM870(old) to CM871(replacement) engine swap, ... someone would be better off keeping the newer electronic VGT turbo and 871 ecm on it, and adapting it to the vehicle instead.

... and in the case of using the 871 and only downgrading it to the CM870 turbo and ecm .. then yes, custom programming needs to be done due to different compression ratio, different injectors, etc.etc. to get it right.

Forum member 'running rough' has experience with 870 - 871 swaps in the past, as he has done this to his own equipment on their farm. He is also able to make the custom settings changes to that CM870 programming if need be.