torinocobra351

I have a 1994 Mustang GT with a 5.0HO engine and I am not sure what the difference is between an HO and a standard engine. I know the cam and firing order is different but what else is different? Where is a good place to get a rebuild kit for an HO?

NeoTokyo

Here is a good amount of info from: http://www.ronmorrisperformance.com/06tech/index.html
Most of the information contained on this page will be directed toward Mustang and Bronco conversions. If you are performing a swap on a different model vehicle, then some of this information may not apply.
If you are installing a complete EFI engine from a late model donor car, into an early Mustang or Bronco, you will need to change the oil pan. You will need to install the correct oil pan for your model vehicle.
If you are doing an Early Mustang EFI Conversion and installing a late model engine into it, then relocating the dipstick and dipstick tube to the timing cover will have to be done. You will have to drill your timing cover. The 86-93 engine timing cover has a place for the dipstick, it just needs to be drilled. The 94-95 timing cover does not have a place for the dipstick.
The 94-95 Mustang timing cover is different than the other timing covers. There is NO place for the dipstick to be installed. This timing cover is shorter than previous timing covers and requires a special water pump. The accessory brackets for these engines are different also. These brackets and water pump move all the accessories back toward the engine. This is great for extra radiator/cooling fan clearance, but if you plan to run air conditioning, you will run into problems. The air conditioning compressor will come in contact with the shock tower. I have heard that it is not even possible to install the compressor on the bracket.
INTAKE MANIFOLDS
There are many different intake manifolds out there to choose from. Mustang intakes are great for a good running stock engine. Explorer intakes are one of the best intakes available, They provide excellent performance for stock and modified engines. The factory Explorer EGR spacer will not work in Mustang or Bronco conversions, it is a 90 degree spacer that puts the throttle body pointing forward. It should be replaced with a Mustang EGR spacer or an RMP EGR eliminator kit.
There are also many after market intake manifolds available that will work just fine for your EFI conversion. Ford Racing Performance Parts, Trick Flow, Edelbrock, Holley and Weiand, to name a few.
If you are wanting to fuel inject a 351W (5.8L), then your manifold selection is limited. Ford Racing Performance Parts, Trick Flow and Edelbrock all make intake manifolds for the 351W.EXHAUST MANIFOLDS or HEADERS
It may be necessary to replace the exhaust manifolds or headers of your swap engine. You will need to install headers or manifolds for the model car that you are installing your EFI engine into.
Late model Mustang shorty headers will not work in an early Mustang or Bronco. You could use your stock exhaust manifolds, shorty headers or long tube headers with an EFI conversion. Which ever you decide to use, just make sure that the O2 sensor is installed so that it can sample exhaust from all cylinders on that one bank.
FIRING ORDERS
Another thing to remember when doing an EFI conversion is that there is 2 different firing orders for small block Fords. Early 289's, 302's and some late model 302's run the 15426378 firing order. Late model 302 HO's and 351W run the 13726548 firing order. Installing EFI on the 15426378 firing order is possible, but does not yield the same results as the late model HO firing order. When you mix, match these firing orders you may encounter some driveability problems like poor idle quality. The Mustang EFI system is a sequential fuel injection system, which means that the injectors are fired in a firing order just like the spark plugs. Mixing these firing orders (spark plug & injectors) can cause a rough idle and poor driveability.
If you are building an engine for an EFI conversion, make sure that the cam you install has the 13726548 firing order.
Some people may tell you that all you have to do is rewire the injectors to change their firing order to match your cam or engine. I can tell you from experience that this does not work, it causes erratic fuel control, back firing thru the inatke manifold (at times), rolling or hunting idle and poor driveability overall. I learned the reason for this once I started reprogramming PCM's for different engine modifications. In the Cal Edit Software there is a table called Exhaust Pulse Delay, what this means is that from the time the #1 injector sprays fuel into the #1 cylinder it knows how many crankshaft revolutions it will take before that exhaust (fuel) passes the bank 1 oxygen sensor and so on for every cylinder of that engine.
This also explains why installing long tube headers can cause idle and driveability issue too.
DISTRIBUTORS
Ford EFI systems require TFI distributors. (Thick Film Ignition) 289, 302 and 5.0 distributors are the easiest to come by. 351W distributors are a little harder and more expensive to buy. If you are looking for a better appearance than a stock distributor, both ACCEL and MSD make billet distributors for the 289, 302, 5.0 and 351W.
If you are considering fuel injection for a 351C, A customer told me that a 460 distributor will fit in a 351C block and the 460 came from the factory with EFI. So this would be the distributor to use for a 351C and 460 EFI conversion.
[font=arial]86-93 MUSTANG 5.0 ENGINES
This is the easiest engine and EFI system to install for an EFI conversion, if you find a good donor car, most of the parts are reusable. Parts needed are th

1994mustang50

hey man i got a 94 5.0 HO also and all it has is cold air intake, borla exaust, and a chip..........dude ive had it up to 190MPH and that was 5th gear at 6000RPM i say i could have hit 205mph give or take....and my car has 175,000 miles on it no new parts or anything so 5.0 moters are built for speed.