What are the differences between the 5.4L and 4.6L short-blocks?


Founding Member
Jul 13, 2002
Los Angeles, CA
I want to know what the differences are in the two short-blocks (4.6L Vs. 5.4L)? What are the bore sizes and strokes of both? Also, are any internal parts interchangeable; ie crankshaft, rods, or pistons? Will the heads (3 valve)off of a 4.6L fit the 5.4L short-block?

I know I can probably use Google to piece together all this info, but I know you guys probably know all this stuff already and you would save me a lot of time by posting this info here. Thanks!

Basically what I am looking to do is build a 5.0L block, but I do not want to stroke a 4.6L. I want to get the 5 liters of displacement by getting a larger bore to the 4.6L stroke. I don't want to keep the stock square bore/stroke setup. I want something with a larger bore for a few reasons:

1. I want to unmask the valves as much as possible.
2. I don't want to increase the piston speed unless it is for more RPM.
3. I want to be able (once the valve train is beefed up) to rev the motor to 8000 RPM. Hence not wanting the extra piston speed caused by stroking.

Thanks again for your responses and the info you all provide.
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CBus 06 GT

Active Member
Aug 29, 2006
Columbus, Ohio
The 5.4 has a taller deck height to accomodate a longer stroke, I think it's an extra .5" They both have the same bore. Heads are interchangeable, but you will need a 5.4 specific intake manifold for the 5.4 block. Basically, it's the same as comparing a 302 to a 351W. If you want a 5.0 big bore, you're best bet is to work with a reputable shop and modify your 4.6 block. Sean Hyland has a 5.0 bore kit available. Part of the deal with this kit is you have to re-sleeve the 4.6 block (sleeves are included in his kit) http://www.seanhylandmotorsport.com/2005-07_mustang_GT_engine.shtml