TownsendMack Posted September 9 Share Posted September 9 Hello, we're looking at a potential donor truck to maintain parts for a workhorse Mack. The donor is a 1975 Mack dump truck. The main truck is a 1986 RL688LST Mack 10 spd trdl1070, E6 350 engine dump truck. Are the tranny, running gear, engine, etc compatible for swap? Bolt patterns, mounts, etc? Quote Link to comment https://www.bigmacktrucks.com/topic/74540-donor-truck/ Share on other sites More sharing options...
terry Posted September 9 Share Posted September 9 What model is the dump truck? Chances are the 75 is just a x107 six speed which will not work good with a 350 engine, need to check rear ratios to see if there the same. Terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74540-donor-truck/#findComment-558274 Share on other sites More sharing options...
JoeH Posted September 9 Share Posted September 9 The 1975 is going to have a 2valve ENDT675 or 676 engine. Virtually the same block, but there are some differences. Mostly I think there were bottom end reinforcing changes over time, and the head bolt quantity changed at some point. It'll bolt right in, but it'll be a weaker engine. 675 is a 237 HP engine, 676 is 283 HP. Quote Link to comment https://www.bigmacktrucks.com/topic/74540-donor-truck/#findComment-558278 Share on other sites More sharing options...
terry Posted September 9 Share Posted September 9 The trdl1070 would work good behind a 237 or 285, but the X107 six speed would not be good behind a 350, to much lugging for that engine. Terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74540-donor-truck/#findComment-558283 Share on other sites More sharing options...
fjh Posted September 9 Share Posted September 9 11 hours ago, TownsendMack said: Hello, we're looking at a potential donor truck to maintain parts for a workhorse Mack. The donor is a 1975 Mack dump truck. The main truck is a 1986 RL688LST Mack 10 spd trdl1070, E6 350 engine dump truck. Are the tranny, running gear, engine, etc compatible for swap? Bolt patterns, mounts, etc? I would make sure your front mount is the the same your getting into the years where the front mount was changing to a two bolt mount from the trunnion arrangement on the newer unit! otherwise this would bolt in! also does the newer truck have a charge air cooler in front of the rad? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74540-donor-truck/#findComment-558285 Share on other sites More sharing options...
TownsendMack Posted September 10 Author Share Posted September 10 I appreciate the responses, very good info. It seems like it may be best to look for a newer truck - donor or one less of an adventure to drive. I cant get much more info from the guy selling the '75. I was trying to get a door sticker picture atleast. ultimately, using running gear, or engine, from an older donor sounds like it will make the "newer" current truck weaker. Quote Link to comment https://www.bigmacktrucks.com/topic/74540-donor-truck/#findComment-558324 Share on other sites More sharing options...
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