Here is the dilema. The VIN of my 1998 F-150 Lariat (purchase used) indicates the engine is a 4.6L (VIN 1FTZX176XWKA74056). However, while doing brake work on the truck last week I noticed 5.4l stamped on the left side of the engine. The full information on the left of the engine is "5.4l Alloy RF-F75E6090 C20A". Near the very bottom of the engine is also a very large stamped "W" (which tends to support what the VIN says). Is my engine a 4.6L or has it been switched out for a 5.4L? Ford had no helpful info when I contacted them. They said go ask a dealer but I figured I would try the FTE forum first. Anybody have some info?

Regards
PB Sterling
Norman, OK

 

W in the VIN is a 4.6 Windsor. The W stamped in the block should mean that it is a Windsor block.
Does it have plug wires or COPs? If wires, then it is a 4.6L.

 

One small correction Jimmy....the W is a 4.6 Romeo, a 6 is the 4.6 Windsor.
An L in the VIN is a 5.4.
No, it makes no sense why the W is for a Romeo.
The 8th digit in PB's VIN is a 6 so it should have a 4.6 Windsor.

 

Ooops, that's what I meant. A little brain dislexia I guess. I don't know why the 4.6 block would have a 5.4 stamped in it though.

 

Nope, that doesn't make sense.

 

Well, I did go and see a dealer about this. They were able to confirm that the same block was NOT used for both the 4.6 and 5.4. However, they could not explain why it says 5.4L on the side of my engine. The mystery continues.

 

No, they are definately different. The 5.4L block is taller and wider to accomodate the longer stroke. They share the same bore size though.