67RModel Posted October 11, 2022 Share Posted October 11, 2022 What is a 300 Plus engine? I am foggy between the ENDT676 and the E7. I hear this term all the time but don't really know what it is? Was it an E6? A Maxidyne? I know the ENDT676 was a Maxidyne with the tip turbine charge air cooler. Was the 300 plus a fueled up version of this engine or a 2V E6 with more than 300 horsepower? Why didn't they just call it by the amount of horsepower it had....presumably 310-325? Thanks for any answers Quote Link to comment https://www.bigmacktrucks.com/topic/70550-300-plus-engine/ Share on other sites More sharing options...
Mark T Posted October 11, 2022 Share Posted October 11, 2022 300 Plus was a 2 valve 315 HP engine . Wasn't Maxidyne, required multi speed transmissions (like a ten speed) as opposed to a 300 which was 285 HP and worked fantastic with some form of 5 speed. I have no idea why they called them what they did 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70550-300-plus-engine/#findComment-511565 Share on other sites More sharing options...
Makeri_Driver Posted October 12, 2022 Share Posted October 12, 2022 Weren't the 300 Plus engines considered Econdynes? I remember see those badges on the hoods of 300 Plus R's with 10 speeds. Quote Link to comment https://www.bigmacktrucks.com/topic/70550-300-plus-engine/#findComment-511680 Share on other sites More sharing options...
Mark T Posted October 12, 2022 Share Posted October 12, 2022 I could be wrong, but I thought Econodyne came along with 4 valve engines. Same theory, but after the 300+ So you could have got a 4 valve Maxidyne or Econodyne. Back then, HP seemed to do more for maintaining road speed than torque it seemed, so the 300 Plus or later Econodynes did better in road tractors or stuff that was on the hiway more. Again, I may be wrong . Quote Link to comment https://www.bigmacktrucks.com/topic/70550-300-plus-engine/#findComment-511719 Share on other sites More sharing options...
mrsmackpaul Posted October 13, 2022 Share Posted October 13, 2022 10 hours ago, Makeri_Driver said: Weren't the 300 Plus engines considered Econdynes? I remember see those badges on the hoods of 300 Plus R's with 10 speeds. No, well not in Australia, they were Thermodyne and rated at 320 hp We call them a 320 coolpower Apparently 2 valve or 4 valve although I only know of 2 valves 350 later on with series intercooling and they were the last if the coolpowers 285 Maxidyne was a coolpower, 300 Maxidyne was a series intercooled Maxidyne And these were all E6 motors Paul Quote Link to comment https://www.bigmacktrucks.com/topic/70550-300-plus-engine/#findComment-511751 Share on other sites More sharing options...
mowerman Posted October 15, 2022 Share Posted October 15, 2022 I ran a 300 four valve In A U model I thought the engine was a dog and it sounded like shit did not sound like a Mac engine at all … bob Quote Link to comment https://www.bigmacktrucks.com/topic/70550-300-plus-engine/#findComment-512099 Share on other sites More sharing options...
mowerman Posted October 15, 2022 Share Posted October 15, 2022 Prior to that I had a 350 Thermodyne that engine was a lot healthier pull the hills a lot better … Also thanks for that information on the 300 plus I never really knew anything about them either except they were pretty good engine performance wise… Bob Quote Link to comment https://www.bigmacktrucks.com/topic/70550-300-plus-engine/#findComment-512100 Share on other sites More sharing options...
roadranger Posted November 23, 2022 Share Posted November 23, 2022 Drove a Superliner with a 300+ and a 13 Spd Roadranger around 1979. It had a turbo driven intercooler on the drivers side of the block that whistled like crazy Quote Link to comment https://www.bigmacktrucks.com/topic/70550-300-plus-engine/#findComment-515796 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.