sorry if I am duplicating a topic here, but I searched for this topic and couldn't find anything. Is there a company who makes an underdrive pulley set for the V10, same as the kit for the 5.4L?? Just wondering. Somewhere I thought I read that the 5.4L and 6.8L are basically the same on the front of the engine.

 

Pretty much, they are.

Not sure if they use an 8-groove or 6-groove pulley on the 5.4 though.

Check your V10 My '01 has the 8-groove pulleys.

Best bet, go to a used truck dealer and pop the hoods on the same year V8 and V10

Thing is, the V10 is big enough that there is no need for underdrive pulleys, especially on a truck. Remember, the water pump will slow down, alternator, etc. Got big tires? That's a pain with an underdriven power steering pump

 

save your cash and time .if your not racing it you don't need them. and no i have not seen any for a v10 yet

 

I you had upped you cruise speed rpm dramatically by going with a real low gear set like 4.88:1 or lower there might be a good mechanical reason to under drive the FEAD (Front Engine Accessory Drive) to get the alternator slowed down a little

Underdrive on a street motor is not really a good idea but they really shine if you drag race. I have never bought the super duper fancy billet pulleys. Most of my race motors are underdriven with mix n match from junk yard pulley sets or fabricated special sizes with a local machinist. The hardest time I have is not the pulleys but finding the right length and width belt(s) none of my racing motors is serpentine so that helps some.

If I was going to put all the fancy aluminum pulleys on the front of my 3v V10 just for LOOKS I would consider slightly over driving my alternator for a slightly higher output at cruise rpms and at idle

 

I have thought of doing this many times...

Now where am I gonna find a smaller 8-groove pulley for the alt? ...