kfletch99

Hello all, I have a 1991 5.0

I am trying to figure out all what is done to the car. The previous owner got it as a trade and didn't know much about the car. I got it for a good price so I couldn't pass it up.

He claims-
Fully Forged internals (assuming I can't confirm this without tearing it down)

What I know-
Cammed, no idea what size. Not too aggressive but enough to hear some chop in the idle.
Eldebrock heads
Eldebrock intake
CAI of some sort
MSD ignition
Shorty headers
Aftermarket exhaust with off road H

Its has a T-5 trans with a short throw (that I installed)

Couple of things, the clutch is VERY stuff (typical?)
I am getting at best 100 miles to a tank (running very rich? too big of injectors? bad/no tune?)

Car has around 127,000 miles, guy claims it was rebuilt at 110.







Any help is appreciated!

nitrous_bob

only the '93 had cast pistons, so they can be stock and he made his claim

chop in the idle can be vac leaks, not a cam, you cant assume anything

100 miles to a tank ? are you racing it everywhere ? cuz thats about 6 miles per gallon, and it can get 24

those injectors are stock, so no...they are NOT too big LOL

id do a gear check for starters and look for vac leaks

nitrous_bob

where u at in Michigan ?

im in st clair shores.....bring it by if your close

kfletch99

Rearend gears? Sorry forgot to mention. It has 4.56's.
I got the car from Port Huron. I'm from Chelsea, just west of Ann Arbor.

Im pretty sure its cammed. It doesn't jump in rpms during idle, its pretty steady. It stays with my buddies 99 Cobra from a roll. A dig is pretty much useless with the 4.56s and stock tire.

Bklyn 5.0

As far as the clutch being tight it probably isn't stock. I bought mine bone stock and the clutch was very soft.

That mileage is terrible, maybe timing, bad o2 sensors or a bunch of other possibilities.

mjr46

clutch cable may be bad, which is what I find with most stiff pedals, I run a cf/df clutch and pedal is smooth, take the 4.56's out, that'll be a big reason gas mpg sucks, also run a koer test and make sure you don't have any codes that'll contribute to reduced mpg, such as rich/lean codes

jthorn9

Well only way to tell if the car has forged internals is to tear it down and see, but I'm gonna go out on a limb and say no, and here's why, nothing is done to the car to justify forged internals.

As stated the chop in the idel can be caused by a lot of things. One semi easy way to check to see if the car is camed is to break out the most accurate ruler you have and pull off the vale and measure the valve travel. If it traves .440" that's stock, .480 that's in the ball park of b303, .500 that's e303 and so on. This isn't 100% or even 90% but it's a good way to get some bearing as to what kind of cam is in there. Just keep in mind there are a lot of aftermarket 5.0 cams with similar valve lifts but different lobe separations, and valve lifts in dual stages.

You have a major electronic or fuel system delivery problem or a bad vacuum leak causing the fuel problem. That car isn't moded enough, even with a mild cam to see those numbers.

As stated pull the 4.56 gears out, that's way too steep. 3.55s or 3.73s are perfect for performance/street balance.

I've driven a lot of mustangs and a stiff pedal seems to be the norm with stock clutches, but as stated there could be a problem with the clutch cable or other causing it to be overly stiff. If it has an aftermarket clutch I would deffinitely suspect the cable.

mattdel

Not to be a killjoy, but if that engine was rebuilt 17k miles ago, it wasn't cleaned during it. That lifter valley & those pushrods have at LEAST 100k on them worth of buildup.

kfletch99

Why would the guy put aftermarket heads on a stock cammed car?

jthorn9

Because a lot of people do that because either they don't know to do or want to pay for a cam job and or think nothing of the cams.