theschwede Posted July 29, 2015 Share Posted July 29, 2015 Hello - I am new to the group. I own 4 Macks; a 1989 Superliner, a 1987 DM, a 1996 RB and a 1997 RB. Looking for a little help please. Anyone know if you can turn a EM7 300 into a 350 or 400, and leave the 6 speed in the truck? Thanks! Tom Quote Link to comment https://www.bigmacktrucks.com/topic/41131-newest-guy-has-two-questions/ Share on other sites More sharing options...
dogg rescue Posted July 30, 2015 Share Posted July 30, 2015 Welcome. We have an e-7 300 mechanical we turned up the pump settings, and 350 injectors, not sure if they were the same as the 300's. It pulls awesome now, still has the original turbo. As for the six speed it can take a lot of power. There is a lot of experts on here that can tell you the specific differences of the engines. Quote Link to comment https://www.bigmacktrucks.com/topic/41131-newest-guy-has-two-questions/#findComment-298428 Share on other sites More sharing options...
rick harper Posted July 30, 2015 Share Posted July 30, 2015 not enough gears to keep it pulling in the sweet spot 1 Quote Link to comment https://www.bigmacktrucks.com/topic/41131-newest-guy-has-two-questions/#findComment-298430 Share on other sites More sharing options...
theschwede Posted August 1, 2015 Author Share Posted August 1, 2015 Thank you both for replying...... Wasn't sure if I had to change crank shaft dampner for the timing on a 350. As far as the transmission, I knew it would handle the torque/horsepower, but was concerned with over fueling between gears. Quote Link to comment https://www.bigmacktrucks.com/topic/41131-newest-guy-has-two-questions/#findComment-298670 Share on other sites More sharing options...
Timmyb Posted August 1, 2015 Share Posted August 1, 2015 Hi Tom. Everyone here are gonna wanna see pics of your trucks...Is the em7 a low reving engine? Anyway, Im confident one of the guys on here can help you out. Quote Link to comment https://www.bigmacktrucks.com/topic/41131-newest-guy-has-two-questions/#findComment-298672 Share on other sites More sharing options...
theschwede Posted August 4, 2015 Author Share Posted August 4, 2015 Yes the EM7 300 is a 1750 RPM engine. Truck will not pull 73,000 lbs over 45 mph. If I pull pump and injectors thinking its a good time to upgrade. Concerned with the steps in the 6 speed. Might have to change trans to a 9 or 13 speed. Don't want to waste money unnecessarily. Believe the truck has a 502 gear ratio. Working on pictures. Quote Link to comment https://www.bigmacktrucks.com/topic/41131-newest-guy-has-two-questions/#findComment-298922 Share on other sites More sharing options...
TeamsterGrrrl Posted August 4, 2015 Share Posted August 4, 2015 An EM7 if it's running right should pull 73k pounds 65 MPH... Sounds like yours isn't running right. Quote Link to comment https://www.bigmacktrucks.com/topic/41131-newest-guy-has-two-questions/#findComment-298935 Share on other sites More sharing options...
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