First upgrades on 89 5.0

I’d probably do a set of rear gears first. Honestly doing the heads, cam, and intake all at the same time is the absolute best way to go about things. Just slapping an intake on with stock heads and cam really won’t do a lot.

There’s no such thing as a maf or throttle body that’s “too big” as long as the car is tuned to accommodate. I’d just go to a 75mm tb, but if you can find a used 70mm for a good deal that’s fine too. Then a 76 or 80mm maf would be good.

Hate to be a fan boy but if you contact Ed Curtis (have one of his cams in the 331 in my Coupe) he can line you out on the heads, cam, and intake (sells all of that) as a package and it will absolutely work. I will say that if you can find an off the shelf cam and you do not have a few months to wait for one of his custom grinds then do that route.

I think your head's in the right place, but I recommend against the Edelbrock 7123 (Performer RPM II) until you're ready to spin the motor and it's making good power at and over 6k RPM, and you won't be ready for that without Heads/Cam/Valvetrain. Nothing runs down low better than the GT40 series (Cobra, Tubular, Explorer) and Edelbrock Performer intakes. If you know you'll make it to the Heads/Cam, then getting ahead of the curve with a Performer RPM or Systemax is still kinda wrong, because you're not going to greatly benefit from the intake as it may actually hurt you down low and other restrictions prevent it from helping you up high. So, in the case where you know you'll go heads/cam, then you might as well do the Heads/Cam/Intake all together.

Here's a little road map for a bolt-on fox:
1) subframe connectors
2) Long-tubes
3) GT40/Edelbrock Performer
4) Gears
5) Tires
6) King Cobra/ Ford HD clutch
7) Rear suspension
8) Heads/Cam
9) JATO rocket

What’s the JATO rocket upgrade?

It all comes down to a few things. These cars have been around 40 years now and everything has been done to them.

Determine
1. what your budget is
2. what your use case is- DD, Street Driven, Street /Track,, weekend toy
3. The more you modify, it's a slippery slope


You get two of the three so pick em
1. cheap
2. fast
3. good
As you always have the money to spend the money and do it right the 2nd time.

Before you start modding anything, I would spend the money on new hoses, belts, bushings, struts and any other worn/broken wear items.

As I said, there have been hundreds of write ups on the first 5 or 10 things to do to these cars. IMO, at a minimum I would

1. gears 3.55 for T5 3.73 for AOD
1.A. Subframe connectors- EVERY fox body needs them. I prefer MM full length welded in
2. Shifter- hurst, Steeda, MGW for a T5, only real option for AOD is a B&M
3. cat back exhaust- pick the one that sounds the best- Flowmaster, Dynomax MAC, Bassani
4. LED dash and interrior light bulb replacement
5. Brakes- cheap and great upgrade is the MM upgrade kit- SS lines, Caliper bushings, Hawk Pads and shoes.
6. Bump the timing to 12-14 degrees- free and it will wake the car up

EVen though it may be slow, there is nothing like jumping in a relatively stock Fox Body and being able to drive it anywhere without worrying something gonna fail or break.

IF you want to upgrade the TB, grab one off a 93-96 explorer and mod the shaft. 70MM is way too large and you will lose low end, but I highly doubt you will feel anything for the effort. headers on a stock motor are IMO a waste of time and money unless you are going for the sound. LT headers on a stock motor are maybe 15 HP but a PITA and make spark plug and starer changes harder.

Of course!! Yes, second the Jato rocket upgrade.