auto307

hey all,
i posted a while ago about dropping a 4.6 DOHC cobra engine in my 97 GT. started thinking, i wasn't sure if it's possible to drop a 5.4L into my 97 GT without major modification?

from what i gathered before, the DOHC will just drop in with the wiring/ECM or ECM reflash on the stock GT computer.

same idea with a 5.4L ?

thanks for the input

sv650lex

I know it's an old post but I'm also woundering about a 5.4 swap. What is the differance in the motors.

900RR Puzzle

I would like to know the answer to this as well.

I know that if you use a truck motor, the intake is WAY too tall. There may be an aftermarket intake that will work now, or spacers to put the 4.6 intake on the 5.4 (the 5.4 intake is wider).

crazy horse

Like you said, the intake is too tall and you wouldn't want the truck intake anyway. If you stay with a 2v it should be pretty straight forward. We swapped the 4.6 in my dads f150. Trying to use a 3v was all sorts of headaches, but the 2v goes right in.

Unless your getting the engine for cheap though I wouldn't do it. Mod motors are worthless for N/A power, especially the 2v's.

Stevecooper

its not worth the effort if you are staying with a 2v. spend the money on a forged bottom end and add some boost.

sv650lex

The forged bottom end with boost seems to be everybodys answer. I haven't done a lot of searching but I imagine It's a couple grand for good forged internals and another couple grand for a good supercharger. I can get low milage 5.4l motors for about $1000.

I'm just wondering is the 4.6 and 5.4 basically the same motor externaly, like the GM 4.8, 5.3, and 6.0.

crazy horse

Yes. You will just need to figure out something for the intake.

There's a reason everybody ends up going with a supercharger. Like I said, these motors don't respond well to N/A bolt ons. Sure you can spend half as much swapping in a 5.4 and get a good improvement over stock (assuming you find something other than the truck intake), but your still going to be limited to where you can go with it.

You can just get the supercharger and still make more on a stock engine than you could hope to make with 6 grand into a n/a 2v mod motor. If you forge it, the possibilities are endless.

I can't wait to get rid of my 4.6, but trading it for a 5.4 is like putting a band-aid on a broken leg.

sv650lex

Don't get me wrong I would love to build the crap out of this motor. But I have 150,000 on it. It runs very strong right now and doesn't use a drop of oil. I'm just looking to get a little more power when this motor finally needs replacing. The 5.4's I've found are cheaper then the 4.6's. That's the main reason I was thinking about the 5.4.

Also I need the motor to be reliable and get somewhat good milage for long road trips. 4,000+ miles

crazy horse

Well if that's the case then it'll probly work for you. Just didn't want you to get the wrong idea like everyone (including myself when I got mine) does thinking the 5.4 will be a miracle. It'll definitely be an improvement over the 4.6 though, especially in the torque department.

I'm not sure what you can do about the intake, someone may make an adapter to use the 4.6 one. You may still run into hood clearance issues.
You will almost definitely need to do some custom work to the exhaust.
Other than that I think it was a straight forward job in my dad's truck. Then again they came stock with 5.4's. Not sure about how all the accessories will work in the car.
You would ideally want a custom tune to take advantage of the new engine.

fastbackford351

kar kraft makes intake adapters for the 4.6 to 5.4 swap. When my 4.6 dies in my GT I want to go with a 5.4. Full floating piston setup like the old FE's with forged internals is a tough combo.

http://www.karkraft.com/new_page_4.htm


btw, according to their website they are going out of business. Which sucks. They have some really neat carb packages for the modular engines.