[XMLViking]

Hi,

I'm pretty much an engine illiterate and trying to educate myself.

I was just wondering if I can get an aftermarket upper manifold(Geads, valves and cam) for a Dual Overhead Cam like the bullet for my 99 Mustang GT.

Incidently has anyone replaced any rocker arms on the 4.6 if the Ford SOHC has them...I'm assuming they do? No pushrods right LOL

I read somewhere where you can get like 34hp boost by replacing the the stock rockers and putting on some sweet ones...

XmlViking

[Nazz]

The DOHC is a whole different animial.

[XMLViking]

Yeah but can't I replace the entire upper portion of my engine and purchase everything above and put it on my existing engine? i.e. the heads....rockers etc...

Or do I just buy a new one from say DSS?

[Nazz]

If it were me i would just buy the whole motor..

[XMLViking]

Originally Posted by Nazz

If it were me i would just buy the whole motor..

Ok where can I find spec's on what I could put in my existing motor mounts???

For a stock 99 GT that is! LOL

[Mana4Real]

This has been gone over a few times. Please search the forums to find information about the head conversion... But I will sum it up for you, it's not worth it it.

Rocker arm conversions make a lot of power, so I've heard, but they are also very expensive.

[XMLViking]

I did do some searching but I found a bunch of stuff on 5.0's which is a different animal.

Crap...so what is worth it?

Droping in a new custom engine for say 5 to 6K or just bolting on what I can and get maybe 75hp....

I"m not sure I can even get 45hp from most peoples accounts. Maybe I just drop in a Cobra Engine in my GT! LOL

Can you do that....again where can you find spec's on what you can and can't put in a Stock 99 GT

Thanks all

[BlueStreak03]

Well, if you're talkin about 5-6 grand then maybe you should look into a blower. You can check out the sigs on here and look at the guys with blowers real closely. They are putting down >400RWHP for the most part with a good blower and intercooler and tune. 5-6 grand won't get you much in the way of a custom mod motor, a new block alone will run a grand at least. As for bolt ons...you're right, they don't do much by themselves but if you think down the road on an ultimate goal and do your mods in an order that makes sense then they will work together to compliment each other. Then down the road when you go for the gusto (i.e. blower, custom motor) you'll already have the little things knocked out.

[Mana4Real]

A new machined block is around $300

[Nazz]

The block used in the DOHC engine can hold more HP and in my experience (I have 1 of each engine) the DOCH also runs quite a bit cooler..

[meatball]

Originally Posted by XMLViking

I did do some searching but I found a bunch of stuff on 5.0's which is a different animal.

Crap...so what is worth it?

Droping in a new custom engine for say 5 to 6K or just bolting on what I can and get maybe 75hp....

I"m not sure I can even get 45hp from most peoples accounts. Maybe I just drop in a Cobra Engine in my GT! LOL

Can you do that....again where can you find spec's on what you can and can't put in a Stock 99 GT

Thanks all

Things you can do:
1) have your heads CNC-ported, add cams, exhaust, other little things = add 60-80hp (remember you have formed powdered metal rods and comparitively weak pistons for extreme horsepower)
2) add supercharger to your existing motor = add 125+hp
3) swap to complete Cobra motor, have link if want.
4) sell car, buy 5.0 92 or earlier Fox body; sell car, buy Cobra
5) You really don't want to start w/little bolt-ons w/o a plan and goal!
6) Another 75hp as you stated a few sentences back would transform your car more than you know.

[kit]

Originally Posted by meatball

Things you can do:
1) have your heads CNC-ported, add cams, exhaust, other little things = add 60-80hp (remember you have formed powdered metal rods and comparitively weak pistons for extreme horsepower)
2) add supercharger to your existing motor = add 125+hp
3) swap to complete Cobra motor, have link if want.
4) sell car, buy 5.0 92 or earlier Fox body; sell car, buy Cobra
5) You really don't want to start w/little bolt-ons w/o a plan and goal!
6) Another 75hp as you stated a few sentences back would transform your car more than you know.

He's right 75 horsepower is a lot of power. You could drop in the cobra motor, but it would cost more than 5-6K.

[snakepit]

From what I can recall, the ford 4.6 Mod motor is compatible across the board. In other words, you can mix and match parts. Everything should just drop into place. The article I read was in Muscle Mustangs and Fast fords. The DOHC heads are driven by a single sprocket (having the exhaust cam driven off from the intake cam by an additional chain). To the same degree, the intake plenum will also fit too. However, I do think that the crank shaft is different than the GT in that it is fully ballanced. The only difference other than 4 valves per cylinder is the valve cover. I think that even the 5.4L mod engine shares a few things as well (except the displacement). For what it is worth, to get a few ponies? you may be better off installing a blower on it than changing the heads. Just an FYI. Just to what would be necessary for the mod is uncertain.