M813a1 engine swap

[Cummins50bmg]

I have a 1971 am general m813a1 and I would like to swap the 250 cummins to a bigger/turbo model Cummins possibly the big cam 400? Does anybody know what series Cummins motor will be best to do the swap, I would like to be able for it to bolt right up if possible or what would need be modified? Thank you

 

[simp5782]

I have a 1971 am general m813a1 and I would like to swap the 250 cummins to a bigger/turbo model Cummins possibly the big cam 400? Does anybody know what series Cummins motor will be best to do the swap, I would like to be able for it to bolt right up if possible or what would need be modified? Thank you

Front engine mount and exhaust has to be modified.

The small and big cams are identical blocks.

Even the bellhousings interchange

 

[Cummins50bmg]

Front engine mount and exhaust has to be modified.

The small and big cams are identical blocks.

Even the bellhousings interchange

Thank you I don’t mind doing stuff like exhaust and engine mount just important stuff like starters and bellhousings

 

[simp5782]

Thank you I don’t mind doing stuff like exhaust and engine mount just important stuff like starters and bellhousings

Yes

The bellhousing for the small cam you have now is an sae 2. It will bolt to the big cam except for one bolt that you must mill the
Bellhousing out. It is near the cam since the big cam offsets the bolt

 

[Cummins50bmg]

Yes

The bellhousing for the small cam you have now is an sae 2. It will bolt to the big cam except for one bolt that you must mill the
Bellhousing out. It is near the cam since the big cam offsets the bolt

Ok thank you for the info, also what engine do you recommend I use

 

[simp5782]

Ok thank you for the info, also what engine do you recommend I use

Doesn't matter In the big cams all they need is more boost and fuel and you get more power

 

[swiss]

Big Cam if you want to drag race down the road!! Love the 400