I have an 03 5.4 with the r100w or something like that. what is the most hp i could get out of it?

Does anyone know what a thunderbolt single chamber race muffler is like. i was thinkin that or borla

 

That depends, how much money do you got? I ask because HP and money walk hand in hand. The muffler I'm not sure, if you looking to see gains from that you will be disappointed, just changing the muffler is more for the sound and a little flow. I would go with the borla because I know a few guys on here have them and they love em.

 

Unless you have a 7700, Lightening, or was swapped, there is only a .01% chance you have a 4r100. The transmission is most likely a 4R70w. I would worry about about getting upgrades like a supercharger before you need a stronger transmission.
Borla or bust. Not even a close decision vs. any chambered muffler.

 

Thanks for shedding some light Otto.

 

How so? the owners manual says 4r100

 

What is the trans code on your door jam? It's the 13th digit on there.

 

the 12-17 are just production sequence. In the door jam ny tranny code is E. Why would that b rare is it cuz they are mostly on lightnings or what?

 

Yeah the 4r100 was only used in the F150 7700, Lightenings, and Superduty's with the 5.4L. There were a few 4r100 put into regular suspension F150s, but they're as rare as unicorns. Now I'm really confused because the trans code E is suppose to be an E4OD, but they quit using those in 98 with the 4r70w taking its place.
Any way it is, the tranny is plenty strong enough to handle bolt ons.

 

Yea im pretty sure the 4r100 came out bout then as well, but i guess not everyones an expert!

 

The E4OD got re named to the 4r100 and came out with the 4r70w for the motors in the late 90's. To know for sure look at how many bolts are on the transmission pan 14= 4r70w 20= 4r100