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Hello good people! Im looking to swap a 4bt or 6bt in a 1977 Dodge Sportsman, class c RV, depending which would be simplest, cheaper and fuel efficient; give or take. Its a 22ft RV, weighs around 10k lbs. It has a 360, duelly and not sure what trans. Im leaning to the 4bt due to space, hoping it'll drop right in. I have no idea if i can use the same trans or what to swap. Main objective is to gain Mileage. Im aware the cost would not lead to savings, and would eventually want to go to biodiesel. If anyone has experience swapping a cummins into 70s dodge, please help me out. Thank you for reading this post.
 

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The 4bt would be more compact but the 6bt would be better suited to the load and cheaper. There have been some Ford campers done but don't remember if there were Dodge's. If you stay with an auto transmission you'd probably want the 47RH out of a 1994-1995 Dodge Cummins. In fact, that engine/transmission combo would be great. If you could find a donor truck from those years you could get most of the needed parts. Be even nicer if the donor was a dually. The you might swap rear ends too. Don't know that anything will be a bolt in, but it's always nice to dream. Time to get out the ruler and start measuring.
 

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Most OTR Allisons will bolt up directly to a 4 or 6BT. The engines & trannies are both SAE3. From the old At 545's to the newest 6 speed, dual OD's. I know because both have been bolted to my 4 banger (I swapped the 545 it came with for the newgen).
 

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We have previously discussed the B series Cummins engine going into the Dodge van chassis. IIRC, there is an issue with the height of the engine conflicting with the heater and dash. The height of the engine has an interference problem when fitting it into the chassis and body. You will need enough clearance to remove the valve covers to adjust the valves or replace a valve cover gasket. If the clearance isn't there you will have to remove the engine to complete this servicing.

The only logical way around this issue MIGHT be using a dash assembly from a P30 stepvan where you would replace the instrumentation [speedometer] with the Dodge stuff. No guarantee that this would work.
 

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Discussion Starter #5
Thanks everyone. The height issue is disappointing to me. I guess ill fix up the 360 for now. I will have to save some serious bank to do it properly.
 
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