I’m picking up my first 7.3 next week—a 1996 F-250—and I’m super excited. I’ve been researching performance and reliability upgrades, but I wanted to ask the community here for advice. I’m looking for simple mods to improve longevity and daily driveability. I don’t plan to turn it into a high-horsepower truck or a racecar, and I won’t be towing often.
Here’s what I’ve already planned:
New air filter/intake (S&B or 6637)
Hypermax intercooler
Hydra chip
New torque converter (for E4OD)
Here’s what I’m unsure about:
Best transmission cooler for steep hill driving at highway speeds
Best parts to reinforce the transmission (looking at Suncoast rebuild kit)
Other mechanical or engine bay upgrades I should consider
I’m open to any suggestions, even if it’s not something I’ve mentioned.
@Cedar
Thanks for the detailed response! I’ll definitely add gauges (planning on pyro, trans temp, boost, and fuel pressure). Injectors are already done. Adding a downpipe to my list. What’s the high-pressure crossover?
It depends on your goals. OBS 7.3 trucks can get expensive if you go down the performance path. For a daily driver/tow rig, here’s what I’d do:
Pull the engine and reseal everything (except head gaskets unless needed).
Add ARP head studs one at a time.
T4 turbo setup with an intercooler.
180/30 or 205/30 injectors.
Super Duty 17* HPOP with new lines and HPX.
Melling LPOP.
E-fuel conversion.
Good CAI and exhaust.
Flush and refill coolant with ELC, and replace the thermostat, water pump, and radiator.
Glow plugs, relay, and harness.
Upgrade battery cables and alternator if needed.
For the transmission:
Healthy autos need a triple-disc converter, upgraded valve body, deep pan, and a 6.0 trans cooler.
Manuals should get a twin-disc clutch and fresh fluid. Upgrading a ZF5 to a ZF6 is a big improvement.
If the engine leaks oil anywhere, pull it first thing. It’s easier to reseal and upgrade everything while it’s out. My ZF6 7.3 made 500+ hp, towed great, and got over 20 mpg on 35” tires. Do it right once, and it’ll last forever.
Marin said: @Ari
Thanks! I want this truck to last forever—it’ll be my daily driver. Is there a specific order you’d recommend for these upgrades?
For me, reliability comes first, then power and efficiency. Refresh the cooling system and address any leaks. A Warren Diesel transmission is worth considering—they’re in and out same day if you’re local. Little details like cleaning the engine bay and replacing hardware make a big difference too.
Adler said:
A 6.0/Mishimoto trans cooler is a night-and-day difference.
Did the 6.0 use the E4OD too, or am I misunderstanding?
Not exactly, but the 6.0 trans cooler is a direct fit for the 99+ 7.3s. Mishimoto also makes a kit with the necessary fittings since the 6.0 uses 1/2” lines and the 7.3 uses 3/8”. The Mishimoto cooler is pricey compared to the stock 6.0 replacement though—$100 vs. $400.