Hey guys I have a 1999 4.6 gt and the engine is shot. I wanted to swap my 5.4 from my 1999 f150. I’ve read many posts and From what I understand is that all I need to do is get an adapter plate to use the 4.6 intake manifold. Then use everything else off the 4.6. Does that sound right to you guys? Thanks in advance.
4.6 to 5.4 swap help.
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Cody7011
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Hey guys I have a 1999 4.6 gt and the engine is shot. I wanted to swap my 5.4 from my 1999 f150. I’ve read many posts and From what I understand is that all I need to do is get an adapter plate to use the 4.6 intake manifold. Then use everything else off the 4.6. Does that sound right to you guys? Thanks in advance.
Your ‘99 5.4 might not have the P.I. stuff. This article says that most of the trucks went P.I. in ‘00. Are the 4.6 P.I. heads the same as the 5.4 P.I. heads? If they are I’d swap them and the intake over as well. It also states that the 4.6 and 5.4 P.I. cams are the same in the cars and trucks so I’d swap them too if the heads work out. If not it might be slower than your 4.6 was.
http://www.mustangandfords.com/how-to/engine/m5lp-0311-mustang-engine-swap
http://www.mustangandfords.com/how-to/engine/m5lp-0311-mustang-engine-swap
well you could use the truck intake. However it's likely that the hood won't fit.
There are custom 5.4 intakes available.
It would also be handy to confirm the number of bolts on the crank of each motor (6 or 8). This will determine what is needed for the flywheel/flexplate.
+1 about the possibility of non-PI heads. Great call 90lxwhite.
If the goal here is to have a fast car, this may not be it. Lots of work for a marginal (if any) improvement.
Have you priced a salvage yard PI 4.6?
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Early 5.4’s had a forged crank and that’s likely what you’ve got. I suspect it’ll be 8 bolts. You will have to swap the mustang exhaust manifolds, and probably the oil pan. I’m almost certain that you will have npi heads, which is not a bad thing. They produce more torque but lack airflow that a 5.4 really wants. The pi heads would probably be better suited here. If you swap the heads, keep the 5.4 npi cams as they are better. You’ll have a hard time getting a low profile 5.4 intake so the adapters will be your best shot. Even after that, it might be hard to get it under the stock hood. The engine is wider so the exhaust will need some widening to bolt up.
Over all, it’s a fairly easy swap and you will LOVE the torque coming from that 5.4l.
Over all, it’s a fairly easy swap and you will LOVE the torque coming from that 5.4l.
Just curious. Are the car 4.6 P.I. heads the same exact as the truck 5.4 heads? Like is a “P.I. head” a “P.I. head?” Like one part number no matter the application.
*Edit* I forgot about 2v, 3v, etc. So I guess is a 2v P.I. the same no matter what it came out of?
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No, all of the pi heads are not the same, and all of the npi heads are not the same. The 5.4 heads in both pi and npi form have larger exhaust ports from the get go, and the water jackets inside the head are larger around the chambers. The heads can be used interchangeably but in stock form, the 5.4 heads are better.
Cool. How about when it comes to the stock valvetrain? Can one handle more lift than the other?
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The pi heads will take more lift that the npi heads, but when comparing 4.6 to 5.4 they are the same.
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