This 1977 Ford F-150 4x4 Build Will Never Be FinishedPosted in Project Vehicles on July 5, 2016
The joke around the campfire is that no project is ever really done. This is more accurate for off-roaders than other automotive hobbies because we go out and beat on our rigs, so even if a vehicle is done it can get undone after a few hard trails. That is the point we were at with Raymond, our 1977 F-150. We had done all of the big upgrades, like 1-ton axles with Detroit Lockers and a 460 engine from LA Speed. After we wheeled this truck for a couple of years, things needed to be freshened and we wanted to improve other aspects to make the truck more functional.
The first change we made was replacing the carburetor with throttle-body fuel injection (TBI). The Holley Truck Avenger carb we were running worked very well off-road at any angle. Unfortunately, the 770-cfm carb was too large for our mild 460 and its tiny camshaft. As a result we had a dead spot right off idle that we couldn’t get rid of despite our best efforts. MSD’s Atomic EFI solved the stumble and has greatly increased our fuel mileage as well.
Another area that needed addressing was the brakes. While we are running Super Duty axles with four-wheel disc brakes, they are not always capable of safely stopping the truck. The biggest issue was when we took the transmission out of gear and the idle dropped, not producing enough vacuum to power the booster. A switch to a hydraulic booster solved that problem. The hydroboost setup and corresponding master cylinder from a Super Duty truck are perfectly matched to the brake calipers on our truck and improved stopping in all situations. The installation wasn’t a direct bolt-on, but it was easy enough that after a weekend of wrenching using locally sourced parts we were able to get the truck back on the road.
The next (last?) upgrade we plan to make to Raymond is to swap out the original NP435 for a ZF5 five-speed transmission. The NP435 has an excellent 6.68:1 First gear, but it is virtually useless on the street, resulting in a three-speed transmission with huge gaps between the gears. The ZF5 has much smaller gaps, which should make the truck more drivable on the street. And with the Offroad Design Doubler, we still have all of the gearing we need for the trail. The input and output shaft diameters and spline counts are the same between the two transmissions, and there is a factory bellhousing to mate it to our 460. It all sounds easy, but we will report back soon on whether that was truly the case.
Do you have things that bug you about your rig but as soon as you get home you forget about them? We have a whiteboard in our garage where we write down issues that we want to address so we won’t forget about them when we get distracted by mowing the lawn or paying bills.
Even though we tried to keep our truck as low as possible, you still have to jump up to get into it. We were pulling ourselves up by the door panel and managed to break the clips that hold it in place. So this wouldn’t happen again, we replaced the clips with new ones from LMC Truck and added a pair of grab handles from MasterCraft Safety.
Our 460 ate the bronze distributor gear on the end of our MSD distributor in short order. We attribute this to the drag of the high-volume oil pump and the heavyweight oil that we were running in our engine. We have since switched to 5W-30 oil and added a composite gear from Tri-Tec Motorsports. So far so good.
The Atomic EFI bolts to the top of any standard intake manifold in place of the carburetor. The only external sensor that needs to be added is the included wideband O2; all of the other sensors are integrated into the throttle body. Cold startups are much quicker now, and the Atomic EFI got rid of our flat spot.
Nate’s Precision swapped the MSD fuel pump in place of the low-pressure Holley pump we were previously running. If you have a mechanical fuel pump, the installation is slightly more complicated. The Atomic EFI can be run as a return or returnless style. We used a fuel filter from a Corvette that provides the return to the tank and simplifies the plumbing.
Our tie rod is mounted relatively low, and when the 6,900-pound truck encounters an object something has to give. We purchased tube inserts from Nate’s Precision, made another tie rod out of 1.75x0.250-wall DOM tubing, and reused our 1-ton GM tie-rod ends since they were still in good shape.
The brake rotors and pads were glazed worse than the doughnuts Hazel brought to the last staff meeting. We had the rotors turned locally and added EBC Extra Duty OrangeStuff brake pads front and rear to keep that from happening again.
We were running the factory brake booster with a master cylinder designed for four-wheel disc brakes. When engine vacuum was high the brakes were adequate, but when the idle dropped we had to stand on the brake pedal with both feet. And this was with a tiny camshaft that makes plenty of vacuum.
The vacuum booster bolted to a mount on the firewall with a pivot in it. We eliminated this extra mount altogether and bolted the hydroboost from a Super Duty directly to the firewall. The pushrod for the hydroboost was the proper length and bolted right to our existing pedal assembly.
The hydroboost is not centered in the mounting plate, and neither was the hole in the firewall of our truck. The problem was they did not line up, but flipping the bracket on the hydroboost did line up the mounting holes and the pushrod for the hydroboost
The hydroboost has a low-pressure return line to the pump, just like your steering box has. We sourced the hydroboost and master cylinder from a wrecking yard, but we couldn’t use the pump from the same donor since we had already converted to a GM Saginaw pump. Fortunately RockAuto had what we needed, this steering pump intended for a pickup with factory hydroboost (PN 208714) that has two return lines.
The new steering pump did not have a reservoir, so we took the opportunity to add more fluid volume with this aluminum reservoir from Summit Racing Equipment. To complete the installation, we took all of the pieces to Parker Hose & Fitting, our local hydraulic shop, where the hoses we needed were made.
]The Super Duty master cylinder (right) has a larger bore than the previous master cylinder we were running. Stepping up from a 1 1/16-inch bore to a 1 5/16-inch bore moves more fluid to the larger calipers. The tradeoff is that if the master cylinder bore is too large, pedal travel is limited and it is difficult to modulate the brakes.
High-pressure fluid now goes from the pump to the hydroboost and then to the steering box. Low-pressure fluid is returned from both back to the pump, and the big reservoir ensures that there is enough fluid to stop and turn at the same time. We used care and routed all of the hoses away from the headers and sleeved the hoses to prevent any abrasion.
The ZF five-speed transmission (right) is the same overall length as the NP435, as a result of the long tailhousing on the NP435. The ZF5 has an extra gear though and much tighter gear splits than the NP435. It also uses a hydraulic clutch linkage instead of the older mechanical linkage on the NP435.
Reliable brakes are valuable when you head to the iconic overlook at the end of Top of the World trail in Moab. This trail is also 30 miles out of town, so it is valuable to a vehicle that is just as comfortable on the pavement as it is on the trail.