I'm looking at buying a older Peterbuilt 379 with a rebuilt big can Cummins and 13 speed. Any experience with these or opinions welcome. Thanks in advance
Cream of the crop in 1987. In 88 the BC4 cam out with step timing and low flow cooling. Some had step timing. Probably still more dependable than a lot of this newer emission stuff. 6 1/2 mpg was about average. Normal questions. Paper work? Rust? Condition?
Still running a 1986 Big Cam every week. Basic maintenance and keeping the filters changed goes a long ways. Was originally a BC4 but I changed mine over to High flow. Don't lug it down to far, and don't keep it against the governor all day every day.
I don't know too much about the rebuild. But that 13 speed should be a redeeming factor. Makes you ladder up and down without having to wait on the clock for that poor cummins to wind out. Cummins like one RPM, particularly close to high horse. If your torque is say 1300, and your high horse is around 1700 with redline at 2100 you will spend alot of time at or near 1600. If you hear music maintaining cruise speed, you are definately in a very good position with that engine powerwise. Do not waste your time standing on it all day. All that RPM will just go away like a COPD patient reaching for his inhaler at the slightest upgrade.
Ran a few of those. And always enjoyed the 855's. Ran a 87 in a tri axle dump truck. Grossing 74,000 lbs, still got 5.8 for the whole year. Then pulled the third axle and bed off. Pulled logs with it, and MPG dropped to 5.2 over the next 2 years. But averaged loaded weight was 89000 lbs.
i have 83 military general 915 , big cam 3 aswell with allison 4 speed.i forgot rears,what do i need to swap out to get 6.5mpg,i think i will get 5mpg at most.i dont know.
