fordguyhey Posted October 20, 2010 Share Posted October 20, 2010 hey everyone. I have the opportunity to buy a 400 Cummins for a good price and was thinking about putting it in my B75. Does anyone know if I would need to get motor mounts out of a B73 with a cummins in it in order to make this work. Is there anything else that would make this a problem?-Ryan Quote Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/ Share on other sites More sharing options...
vanscottbuilders Posted October 20, 2010 Share Posted October 20, 2010 You will need at least the front mount from a B-73. The transmission mounts are the same. I think.The 855 Cummins is physically larger than the older 74-? cubic inch Cummins used in the B-73. I've been told that it is an easy swap - but we need you as a Guinea Pig.Let me know how this works - as I also have a B-73 and a low mileage 400 Cummins looking at each other lovingly in the shop.Paul Van Scott Quote Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-65602 Share on other sites More sharing options...
vanscottbuilders Posted October 20, 2010 Share Posted October 20, 2010 As a follow-up - talk to Kevin All at All Macks.Not only does he know everything, but he actually built one of these B-73's with an 855 Cummins a few years back.Paul VS Quote Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-65603 Share on other sites More sharing options...
Guest 45LMSWM Posted October 20, 2010 Share Posted October 20, 2010 Phil Wheeler up in New England used to own a restored B75 L-cab that I am pretty sure had a 400 Big Cam under the hood. I believe the truck was sold at some point, but can't remember who wound up with it. Truck was Blue with red frame and full fenders over the rears. Quote Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-65608 Share on other sites More sharing options...
fordguyhey Posted October 21, 2010 Author Share Posted October 21, 2010 As a follow-up - talk to Kevin All at All Macks.Not only does he know everything, but he actually built one of these B-73's with an 855 Cummins a few years back.Paul VSDid all B-73s have Cummins motors or just some of them? I was under the understanding that the only major difference between a B-75 and a B-73 was the engine. I will call Kevin and pick his brain about it too. Quote Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-65655 Share on other sites More sharing options...
terry Posted October 21, 2010 Share Posted October 21, 2010 B75 is a non turbo mack engine a B753 is a turbo mack engine, a B73 is a non turbo cummins, a B733 is a turbo cummins, anda B773 is a turbo cummins. Gets pretty confusing! Terry Quote Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-65665 Share on other sites More sharing options...
theakerstwo Posted October 22, 2010 Share Posted October 22, 2010 I see two problems. The front mount on a B73 was a trunion mount meaning it was a rap around the center trunion that some old cummins had around the crank on the front cover. I have seen these mounts up later on 855 engines but have never seen one on a big cam. The best thing is use the front mount from a big cam and build your cross member that it sets on. The other thing is the flywheel and clutch will be a pull type if using the old mack trans.The flywheel from a 220 will not be same as a 855 engine. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-65671 Share on other sites More sharing options...
fordguyhey Posted October 23, 2010 Author Share Posted October 23, 2010 I see two problems. The front mount on a B73 was a trunion mount meaning it was a rap around the center trunion that some old cummins had around the crank on the front cover. I have seen these mounts up later on 855 engines but have never seen one on a big cam. The best thing is use the front mount from a big cam and build your cross member that it sets on. The other thing is the flywheel and clutch will be a pull type if using the old mack trans.The flywheel from a 220 will not be same as a 855 engine.I see what you're saying about the mount. I guess I'll just fabricate off of whatever is on the big cam. As far as the pull clutch goes I've already got a swinging pedal and cable assembly out of an R model installed in my cab so I'll just need some bracketry underneath to support the cable and I should be all set. Quote Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-65736 Share on other sites More sharing options...
Truck Shop Posted August 22, 2018 Share Posted August 22, 2018 On 10/21/2010 at 6:10 PM, theakerstwo said: I see two problems. The front mount on a B73 was a trunion mount meaning it was a rap around the center trunion that some old cummins had around the crank on the front cover. I have seen these mounts up later on 855 engines but have never seen one on a big cam. The best thing is use the front mount from a big cam and build your cross member that it sets on. The other thing is the flywheel and clutch will be a pull type if using the old mack trans.The flywheel from a 220 will not be same as a 855 engine. Yes Cummins did make big cams with a front trunion mount. I have a 400 BC II CPL 449 setting in a Freightliner frame that has the front trunion mount. I know this is a old thread but-Cummins did make them. Truck Shop 1 Quote One ping only Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-404613 Share on other sites More sharing options...
12V71 Posted August 25, 2018 Share Posted August 25, 2018 (edited) On 10/21/2010 at 6:10 PM, theakerstwo said: I see two problems. The front mount on a B73 was a trunion mount meaning it was a rap around the center trunion that some old cummins had around the crank on the front cover. I have seen these mounts up later on 855 engines but have never seen one on a big cam. The best thing is use the front mount from a big cam and build your cross member that it sets on. The other thing is the flywheel and clutch will be a pull type if using the old mack trans.The flywheel from a 220 will not be same as a 855 engine. Old thread... But the 220 flywheel for the CL-50 clutch will work on an 855, I have used it to replace V-8 Cummins engines with the 855 in M-123 Military trucks for farm use. The Cummins part number was 21010. I also had a jig I made to build trunnion crossmembers for the front mount. Oh, you had to drill the clutch housing bolt holes to clearance 7/16" bolts too. They were 3/8" on the 765 V-8. Edited August 25, 2018 by 12V71 1 Quote Link to comment https://www.bigmacktrucks.com/topic/16204-big-cam-400-into-a-b-75/#findComment-404810 Share on other sites More sharing options...
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