Throttlebody

A 65 MM TB will do fine for your setup.
The 96-2001 V8 Explorer came with a 65 MM TB, and if you can locate one it will save you some $$. It is not a direct bolt on and requires some fabrication or modification get the linkage to work. I have some tips for that task at the end of this post if you are interested.

If you aren't into that or don't want to be bothered, buy one that is a ready made to fit.

Can you sing “Whistle a happy tune”? Because that’s what you will be doing with a BBK or Mac throttle body. They have an annoying tendency to whistle at idle.

The best buy is either a Ford FMS or Accufab throttle body. The FMS body comes with a new TPS sensor and IAB actuator, a highly recommended plus if you have and older car and these items haven’t been replaced. The Accufab doesn’t come with these items; you use your current ones. It is an excellent piece of machine work & the fit and finish are first class. It is also more expensive than the Ford FMS throttle body.

Size:
A 70 mm throttle body is a good choice for a stroker, pressurized induction or 351 or larger engine. Use it on a 302 if you are going to spend more time at the race track than on the street, or if you have a really hot combo that likes to rev. Use it on a stock or mildly modified engine and low end torque will suffer due to low velocity in the intake,

A 65 mm throttle body is the best choice for a stock or mildly modified 302 engine. Low end torque is good and the velocity in the intake is right where it should be.

With either size throttle body, the EGR spacer has to match the throttle body for best results. Plan on buying a new one to match the TB, long with some new gaskets.

The intake manifold may need to be ported or replaced to take advantage of the increased airflow capabilities. The Explorer had a 65 MM TB as stock equipment, so a 65 MM TB won't require any porting work do the done.

Larger injectors with an 88 speed density engine isn’t a workable solution, the computer won’t know what to do with them. You can install a custom burned chip, but that will probably cost more than the Mass Air Conversion. Change something else that affects airflow though the engine and you need to burn another chip. Larger injectors work best when you do a conversion to Mass Air Flow like the 89 (or Cali 88) and later stangs. Keep in mind that speed density engines can be fussy about mods that change the airflow or vacuum. That’s why the mass air conversion is such a popular item on the performance mods list.



Modifying an 65 MM Explorer TB to fit a Mustang

The stock Explorer linkage didn't come anywhere near fitting, so I made an adapter plate for the throttle linkage so I could use the 65 MM throttle body.

This is what I did:
Make a drawing of the position of the old throttle body linkage arm and its angular position relative to the centerline of the throttle body. Remove the ball stud off the explorer TB to make way for the adapter plate. Drill and tap a 10-32 hole in the linkage parallel to the TB shaft. Make an angle bracket out of 1" angle iron 3/8", drill a 3/16” hole in the center of each one of the legs. Then bolt it on where the hole was drilled & tapped. Then make a circular adapter plate out of 1/4" thick aluminum to bolt the two linkage arms together. Then bolt the aluminum plate to the existing linkage, and the angle bracket. Next mount the arm with the ball stud off the old throttle body on the adapter plate using the drawing to get the angle correct. You will need an aircraft type countersink for one of the bolts that secures the plate to the explorer linkage arm. It ends up being under the arm with the ball stud for the linkage. It works great and looks neat.

The Explorer TB could have been real simple if I had a gas welding torch or taken the TB to a welding shop. Just grind the mushroomed part of the TB shafts so that you can pry the linkage arms off. Then swap the stock arm onto the Explorer TB and braze it onto the shaft. It Takes about 3 minutes or less worth of work with the torch, so it shouldn't cost much.

I didn't have access to a welder, so I fabricated the plate in my shop. I took about 1.5 hours to do it, it was a measure, cut, and fit type of operation.

Also see http://www.veryuseful.com/mustang/tech/engine/ConvertingExplorer65mmTB.pdf for modifications to adapt the 65 MM Explorer TB to a Mustang

Thumbs up on the 65mm tb! I had your same set up on my last fox, and the 65 was a good addition. Won't see huge gains with stock heads though...

karthief said:

Mine (bbk) whistles a happy tune, drove me batty for months, changed every gasket at least twice before I found out, now dumb ricer kids think my bov is stuck!

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I bought an SVE throttle body from LMR that whistled at idle. Did a little research and found it was most likely caused by the air going across the sharp edges on the holes into the IAC. A little smoothing of the edges of the holes with a dremel.........no more whistle.

karthief said:

Mine (bbk) whistles a happy tune, drove me batty for months, changed every gasket at least twice before I found out, now dumb ricer kids think my bov is stuck!

Click to expand...

Just say you have a supercharger.

TB upgrade at that level is a waste of money. Keep the stock one. When you're ready, always match the TB to the inlet of the manifold. No, bigger TB's don't hurt 'low end torque'.

I'm not worried about losing low end torque but I wonder if I'd see any gain with a 70mm. I'm still using the 65mm I've had for 20 years. But now have much more cam, 80mm meter and rpm 2 intake.
What's your opinion @jrichker?

skiwesser11 said:

I'm not worried about losing low end torque but I wonder if I'd see any gain with a 70mm. I'm still using the 65mm I've had for 20 years. But now have much more cam, 80mm meter and rpm 2 intake.
What's your opinion @jrichker?

Click to expand...

Stock or aftermarket heads?
Stock heads; keep your 65 MM, a 70 mm won't increase the airflow since the stock heads are the restriction to airflow.

Aftermarket will see some improvement, it is difficult to say how much.

jrichker said:

Stock or aftermarket heads?
Stock heads; keep your 65 MM, a 70 mm won't increase the airflow since the stock heads are the restriction to airflow.

Aftermarket will see some improvement, it is difficult to say how much.

Click to expand...

AFR 165's , Ed Curtis cam, big lift small dur., long tubes, usual accompanying bolt ons... 306ci... T5 (still) I mentioned the intake and air meter...
Would you guess the 65 is a major enough restriction to change? I was going to do an electric fan first but I would not want to find out I'm choking it!
It is a FMS piece. Thanks!
My dyno sheet is posted here somewhere

Thank you gentlemen!
Sorry about the post hijack