Cummins 4BT for sale. Five engines arrived for rebuilding. There are already a few commitments, so let us know right away if you have interest. There will be four total cummins 4BT’s for sale. BB Diesel Performance will keep one for a Jeep conversion DEMO machine. We plan to build the cummins 4bt to our clients specifications. Some want a stock build for improved fuel economy while others are asking for maximum horsepower, twin turbo’s, on and on.