When a Fox 5.0 isn't a Stang!

ratio411

Founding Member
Apr 21, 2002
3,870
73
109
Pensacola FL
225992_1369534656583_1778245963_601353_1139776_n.jpg


My son's 1981 Fox Fairmont... (father/son project)
Originally 200/C4/7.5-2.73
Now 5.0 HO/AOD/8.8-4.10

88 Lincoln LSC 5.0/AOD
90 Stang GT 8.8"
93 Stang GT front steering/suspension
RJM universal harness/MAF conversion
GT40 intake w/65mm TB
Stock MAF
MAC equal length
Dynomax X
Dynomax race bullets
Z-Gate shifter
10 holes w/225-15s
80 Stang scoop (cosmetic)
 
So, what do the 5.0 HO gurus think an aftermarket MAF will do for the car?

It feels like it winds up really quick, and runs out of breath fast with the 4.10s.
The 2.73s wound up slower, and the engine 'felt' like it made power up close to 6k rpms,
but with the 4.10s, it gets to 5k and the nose drops like power fell flat.
It probably lost power after 5k with the 2.73s, but I assume the gearing didn't make it obvious. ???

The only 'real' bottleneck I can find in the intake system is the tiny stock MAF.
The exhaust is WIDE open with the race bullets and such, and the intake is decent with the GT40, 65mm Exploder MAF, and a 1" phenolic spacer. No EGR, cats, or AIR.

Without worring about the stock HO cam or E7 heads, the MAF is the only bottleneck I can see.
I have to believe a larger MAF would help marginally.

Thoughts?
 
Nice looking! A 79 Futura was my first Ford. I bought it for my wife before we got married, back in 83 for $850. I planned to swap in a 302 for the 4 banger, bought just about everything, but ended up just trading it in on my 87 Mustang instead. Wish I could find another one. I don't know much about aftermarket parts, since my car is still stock. :D

Good luck on it!
 
Nice looking! A 79 Futura was my first Ford. I bought it for my wife before we got married, back in 83 for $850. I planned to swap in a 302 for the 4 banger, bought just about everything, but ended up just trading it in on my 87 Mustang instead. Wish I could find another one. I don't know much about aftermarket parts, since my car is still stock. :D

Good luck on it!

Great looking LX you got there!
One of my favorite Fords.
 
A bigger maf would help. I know when I ditched my stock puny maf for an sn95 maf, it did feel a little quicker.

However, the stock heads don't help. Time to ditch the e7s and get some gt-40p heads or better!

But nice little project
 
Let us all not forget.

This is a mustang. It just has a different suit on.

or I'll put it this way.....

W/O this car, there'd be no fox mustang.

Having had 4 of these cars. I am always a fan to see one when it comes to the party.
 
Thanks guys!

My son is 19, and full time student, so real wheelies with AFR heads and custom cam are still a few years off. For now, the HCI are going to stay FoMoCo parts.

The funny thing about the 4.10s is that the 90 GT rear we got was bought thinking the tag said "2.78".
So my son pained for days on what gear to buy. Started off thinking 3.55, but eventually talked himself into the more aggressive 4.10.

The day I put the gears in, when I pulled the bolt off the tag, it exposed a "3" that we or the seller didn't see. The gears were actually 3.27. If we had known that, there never would have been 4.10s.
We wanted more gear than the 7.5 had (2.70 something), and 3.27 would have kept us happy.

I put the 4.10s in though, since we had already begun.
I am happy.
The car runs out of breath quicker, but it still likes the gears very much, as seen in the launch pic.
I have run 4.11s behind engines that shouldn't have had 4.11s, and I know what that feels like. This isn't that feeling. Those cars drove like dumptrucks... This one drives well. I think just a bit more breathing on the intake will do a world of good.
 
I wish I had digital pics of the fairmonts I've built over the years. I don't have to tell you that there is not much you can do to make them unique.

I did have a pretty cool Zephyr. Narrowed 9" pro street Bob Glidden wanna be street car. Other than paint, The only body things I did was get rid of the side moldings, I made a "86 style" mustang grille, and I drilled a hole in the bumper shocks, and pushed them back closer to the car (front and back) so the bumpers wouldn't hang out like Bumper Buck teeth and Bumpers got back. :D
 
I have always wanted a 4-door fairmont. do a 4.6 DOHC swap, 6-speed, IRS, and keep the stock bench seat, and interior. 5-lug swap with GT stuff up front, and run a 15" steel wheel. Keep it all under the stock hood, ultra quiet exhaust, and ICE COLD A/C....

Tell me that wouldn't be a fun car!
 
We threw an SN95 MAF in there today to give it a try.
Runs great, but it's wet out, so we can't try it to it's full potential.
I have to think it would give us a bit more spin after comparing the MAFs side by side.

My son also changed out the break in oil from the rear end and requisitioned my aluminum cover for his own car. (That kid better take good care of me when I am old!)

230647_221451194532468_100000027679711_953196_5411259_n.jpg
 
Very cool car. Back in high school my buddy had one with a straight 6 under the hood. The X pipe with dynomax race bullets was what I had on my 90. Now, it’s 2 into 1 & the turbo. I’m sure your son loves the sound of that exhaust. I know I did. I’m surprised you can just switch out MAF's like that without a way to tune. I guess if they were all calibrated for the 19 lb injectors it would work. The F303 cam helped out a little with mine running out of breath at around the same RPM as yours. I still had stock heads & rockers at the time. One of the guys on here, (smokedya) recommended a PMAS MAF for my project. the guy I talked to said. The 3" slot style has been proven to support up to 900 HP to the wheels. The only problem with that one is, it’s not calibrated to any size injector so you would need a tuner like the TWEECER RT or have a chip made so the EEC would know what to do with it. That might be something to look into. Regardless of his future power goals, he shouldn’t ever need another MAF unless that one just went bad. Have fun doing the father son build.
 
No matter what you do to a fox stang, including removing the 5.0 badges, the import guys still can spot the duals and always want to try ya. IMO the futura is the best of the fairmont body styles, besides a wagon and can be a convincing sleeper. Except when you have really loud exhaust. The project is still cool though.
 
Let us all not forget.

This is a mustang. It just has a different suit on.

or I'll put it this way.....

W/O this car, there'd be no fox mustang.

Having had 4 of these cars. I am always a fan to see one when it comes to the party.

Or to put it another way, the Mustang is a Fairmont, or Zephyr more specifically since they came before the fox chassis Mustang did :nice:
 
Next project is an SN95 electic fan we picked up at the yard when we got the MAF yesterday.

It's a nice big fan, and we have a new adjustable thermostatic switch, so I am going to start figuring out a way to install the fan.

The donor LSC had a nice big alternator, 85 amp IIRC, and the car has very little to run electrically, so I figure as long as we use some heavy wire and a relay, we should be fine power-wise.

As far as the launch goes, as seen in the pic, it is hard and the tires are planted good, but there is a case of violent wheel hop right after launch. So we are also looking into tubular upper/lower rear control arms.