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Building a 70 f250 highboy considering motors. It's between rebuilding the 390 or 6.9 deisel. 6.9 is running. Any options and thuoghts would be appreciated
+1 on diesel with 5 speed. It depends though. What will you be using it for? If you get a diesel you will most likely get better mpg but it costs more per gallon. With work the 390's can make a lot of power. But same goes for diesel.
Wes, I don't know my 4wds as well, but to go diesel, you will need engine, tranny, (maybe transfer case) along with fuel tank, engine perches, to convert.
390 if existing just rebuild. Don't know your experience level, or what kind of budget you have. You should be able to rebuild complete for less than 2 grand.
Yeah, if the 4BT was a choice, I'd go that way too but since it's 6.9 or 390, I don't think all the work to put a heavy wheezing 6.9 would be worth any gain you might get. It's going to be a lot heavier, not really much more power and maybe 2-3 mpg gain on fuel that costs more money. Maybe if it was a power stroke, it would be a different story.
Thank's to everyones replies first of all. Second leaning toward 6.9 because I have a strong runner already getting 20+ mpg needs resealed. Rather have a cummings, but budget won't allow. All in need to install in my 70 model is a bell housing, to run four speed, still looking for a 5 speed. Need a 2wd because of the divorced transfer. Wheight really not an issue, don't play in the mud, more in the mountains and pulling. Don't get me wrong like for it to be orginal but don't have title so that value is lost. Plus everone i've talked to said you'll wear the truck out before the motor. My 87 is proof of that.
I built a 360 for my F250, and it was great. Decent power, but 12mpg empty and 7mpg towing, with 3.73 gears and a four speed. I put in a 7.3IDI with a Banks exhaust and open air cleaner (nothing else would fit), and a ZF five speed. The power is similar up to the mid range, it definitely has less top end but way more off the line grunt so it's a god trade off. It now gets 17-19 empty doing 70, and 14 towing. Doubling your mileage is huge. The fuel is $.45 more a gallon here, so it's not half the operating cost, but it's still a seven cent per mile cost savings. I spent about $600 on my conversion, so the 10,000 miles I have put on it in the last year have paid it all back then some.
There are a few things I would do differently, and the first is more sound control. Most of the noise from a n/a diesel comes from the intake, so having that tuned or at least located further away from the firewall would make a huge difference. Sound control material on the firewall, floor, and under the hood would help a lot too.