66rmack Posted August 30, 2015 Share Posted August 30, 2015 Hey guys new here. Went and looked at a 70 r model and was wondering if anyone could tell me what this engine serial# means? Looking for a 237 and 5 speed to repower my dads 66 r model that has a 711 turbo and a 5 and a 4. The serial # I found on the engine is ENDT 6754U902 there was a space after the 0 before going to the 2 but it didn't look like there was anything in the space. Any help is very appreciated I don't know much about the macks but I'm trying to get his old dog on the road again it's been in the shed since 84. Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/ Share on other sites More sharing options...
j hancock Posted August 30, 2015 Share Posted August 30, 2015 You found what you are looking for. ENDT675 is a 237 HP.That was easy. 1 Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302010 Share on other sites More sharing options...
66rmack Posted August 30, 2015 Author Share Posted August 30, 2015 Sweet thank you! Any chance you know what the other numbers mean? Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302018 Share on other sites More sharing options...
Bigdogtrucker Posted August 30, 2015 Share Posted August 30, 2015 Why swap out the 711/quad? Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302022 Share on other sites More sharing options...
66rmack Posted August 30, 2015 Author Share Posted August 30, 2015 The 711 is in need of some help a rod cap came loose and it broke the block. And it's been a dream of his to swap it to a maxidyne since the 711 went down. The quad is loose the old man said it's got really close to 3mil on it and the last time it was apart the case hardening is wearing off the gears. So it needs some help also. Is it worth putting the maxidyne in with the quad behind it? I was just going to swap everything seeing I will have a complete doner truck Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302023 Share on other sites More sharing options...
Superdog Posted August 30, 2015 Share Posted August 30, 2015 The other numbers are just part of the serial #. One thing you might want to consider just swapping the engine and leaving the Quad,otherwise you will need to swap rears also,or wind up with a very slow truck. Chances are very good the fastest ratio your rears are now would be 4:50,but more likely something in the 5's like a 5:08 or 5:73. Using the 5 speed,you will need a 4:17 rear to have a 62 mph truck,if it's on 20" rubber 2 Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302024 Share on other sites More sharing options...
hatcity Posted August 30, 2015 Share Posted August 30, 2015 Doesn't the 237 put out more torque than the quad can handle? Quote Success is only a stones throw away.................................................................for a Palestinian Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302026 Share on other sites More sharing options...
Bigdogtrucker Posted August 30, 2015 Share Posted August 30, 2015 Doesn't the 237 put out more torque than the quad can handle?There were lot's of Maxi's transplanted in front of quads(duplex/triplex too) in my area over the years that worked daily for many years. All in how you treat them I'd say. Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302027 Share on other sites More sharing options...
66rmack Posted August 30, 2015 Author Share Posted August 30, 2015 Superdog I'm def not sure what the gears are. But I know with the 711 and the quad it will do 65 mph then he had a 250 Mack in it?(idk what that is I guess cause I couldn't find anything about a 250 in the 70's) When the 711 went out. With the 250 turning 2400rpm he said it would run 72mph. The 250 went out he put a 711 back in it. Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302031 Share on other sites More sharing options...
Superdog Posted August 30, 2015 Share Posted August 30, 2015 Superdog I'm def not sure what the gears are. But I know with the 711 and the quad it will do 65 mph then he had a 250 Mack in it?(idk what that is I guess cause I couldn't find anything about a 250 in the 70's) When the 711 went out. With the 250 turning 2400rpm he said it would run 72mph. The 250 went out he put a 711 back in it.Yeah,you are definitely going to want to swap rears if you go with the 5 speed. Does the truck have 20 or 22 " tires?The 250 was the ENDT673C. Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302032 Share on other sites More sharing options...
66rmack Posted August 30, 2015 Author Share Posted August 30, 2015 (edited) It has 20's on it. The truck I found has bud 24.5. May dad always wanted to swap his to the buds so he could put aluminum wheels on it. So I was planning on switching the hubs over from the daytons. ( I know the purists on here don't seem to like that.) also the truck I found has a 3 speed aux divorced from the maxitorque. Is it possible that one is geared just as low? Edited August 30, 2015 by 66rmack Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302036 Share on other sites More sharing options...
66rmack Posted August 30, 2015 Author Share Posted August 30, 2015 I also wanted to say thank you for the info. It's already been very helpful. I hate to step backwards before I step forwards. Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302037 Share on other sites More sharing options...
Superdog Posted August 30, 2015 Share Posted August 30, 2015 if it has a 3 speed behind the 5 speed chances are good it's got low gears too,especially if it has 24.5's too.,either that or it was geared to fly. Best thing to do before you get into it any farther is see what you have.Ratio is stamped on front right of carrier,flat spot about 4 " square. Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302040 Share on other sites More sharing options...
66rmack Posted August 30, 2015 Author Share Posted August 30, 2015 Thank you very much will do Quote Link to comment https://www.bigmacktrucks.com/topic/41567-engine-id/#findComment-302052 Share on other sites More sharing options...
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