Best and easiest upgrades for my 7.3?

Hey everyone,

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.

This can become a rabbit hole fast! I’ve had my truck for 20+ years, and here’s what I’d recommend starting with:

  • Install gauges first (EGT, boost, engine/trans temp) to monitor everything.
  • Chip (Hydra) with multiple tunes.
  • Stage 1 injectors.
  • Intercooler.
  • Downpipe and open up the exhaust.
  • 6637 air filter.
  • High-pressure crossover (helps smooth idle, but your mileage may vary).
  • Shim the fuel pressure regulator.
  • Bellowed up-pipes.

This list will make a noticeable difference and improve reliability. There are plenty of other upgrades, but I’d focus on these first.

@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?

@Marin
It allows excess oil pressure to flow between both heads, reducing pressure spikes and improving injector performance. Here’s a link: Stainless Steel HPX - Ford 7.3L Powerstroke 94-97

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.

@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?

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.

Straight pipe it!

A 6.0/Mishimoto trans cooler is a night-and-day difference.

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?

Marin said:

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.

Marin said:

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?

The 6.0 didn’t use the E4OD, but the cooler swaps onto 99+ trucks easily. I’m not sure about fitment for OBS trucks, though.

Trade it in for a 6.7.

Phoenix said:
Trade it in for a 6.7.

Maybe someday, but I’m sticking with the 7.3 for now.

Phoenix said:
Trade it in for a 6.7.

Yeah, for $80k and a monthly payment!

Cedar said:

Phoenix said:
Trade it in for a 6.7.

Yeah, for $80k and a monthly payment!

Nah.