I have a friend that bought a work truck that had a bad 5.4L in it. He has looked everywhere for a decent price on a 5.4L but has had no luck. He can get a really good deal on a 4.6L but doesn't know if the tranny from the 5.4L will bolt directly to the 4.6L. I think its an auto, so I'm assuming he will need to switch out the computer. Is there anything else we need to look at?

 

The trans will bolt up. There could be a problem with making it work right, however.

The 5.4L came with either the 4R100 or the 4R70W. The 4.6L only came with a 4R70W. If he keeps the original computer it will run the trans fine, but I don't know about the engine. If he gets a new computer for the 5.4L make sure that it is one that is for a 4R70W. If so, everything should work fine.

 

if you're anywhere near abq i have a 5.4

 

In the long run your friend would be better off paying a little extra to find a 5.4.
The bolt pattern for both engines are identical. If he still opts for the 4.6 make sure that you use a torque converter from a 4.6. It has a higher stall speed and that will allow the little 4.6 to huff a little longer to build up its power.

JMC

 

it would bolt up..but man he wont be happy with going from a 5.4 to a 4.6..haha...you just cant down grade...haha the 4.6 will end up working a lot harder....just not worth saving a buck

 

So how is this project going?

JMC

 

I'd use the 4.6, just add boost Some 5.4's had the high stall converter, others had the low stall. I find usually the vans and heavier trucks have the high stall. Completely the opposite of the way I like to see it done, but hey thats ford for you. IMO more weight use less stall. Lighter vehicle throw some stall at it. Weight is more of a factor than anything to me. You'd probably have to drive them all different ways to see the difference.
Alan