Back in May, we introduced you to a near-stock ’08 F-250 we’d been playing with at the dragstrip (“The Four-link Fix”). And after seeing what the truck could do with just a tune and nitrous, we started thinking about the bigger picture... With a lighter curb weight on its side than your typical four-door rig, we decided the standard cab XL model Super Duty would be the perfect candidate to send down the track in a hurry. The end goal is to make some good, old-fashioned, fuel-only horsepower with the truck—and run 10s in the quarter-mile.
| 2008 Ford F 250 International Threat Part 1 2008 Ford Super Duty On Lift With Transmission Out
Knowing that we’ll need at least 850 to 900 rwhp to reach our goal, we’re getting started this month with a bulletproof foundation: building up the 5R110W TorqShift automatic. With harsh-shifting strategies and heavy trucks killing a lot of modified TorqShifts these days, our plan is to see if we can get one to live in our 7,000-pound test mule—and with spot-on transmission tuning. Answering the call were our friends at River City Diesel, and after spending the day at the company’s East Peoria, Illinois, facility, our stock 5R110 was transformed into one of its Super BA transmissions.
| River City Diesel owner, Josh Davis, performed the transmission build for us. He got started by removing the factory transmission pan, followed by the internal filter and solenoid body. Keep in mind: We were disassembling a working transmission with only 60,000 miles on it so we weren't really expecting any surprises once inside it.
The No Frills Build
With the 5R110 fortified, we’re moving on to the 6.4L V-8 under the hood. Next time, we’ll be pulling the cab and modifying the last International-built Power Stroke for all-out horsepower. This is our tentative power package:
- MaxxForce 7 pistons, R&R forged rods, bottom end overhaul
- Valvesprings, pushrods, cam, lifters
- Dual K16 injection pumps, 200hp nozzles, fuel supply system
- Single turbocharger (T4 mount, up-pipes, and exhaust manifolds)
- Tuning, dyno, and track testing
| Finishing off the build is one of River City’s triple-disc, billet, Ultimate torque converters. For ’08 to ’10 trucks running the factory (or factory-based) compound turbo arrangement, the stall speed sits around the 1,600-rpm mark. But since we plan to ditch the factory turbos and install a big single, we’ll be running a looser converter from River City, one with a stall speed between 2,200 and 2,400 rpm.
