[WickedSnake00]

Originally Posted by Green_6er Well, i didn't really know where to post this so the mods can move it if yall want. but my question is about engine swaps. My state laws dictate that to do an engine swap, it has to have been offered as a factory option in the car. so I have a 2000 v6 mustang, and i was wandering if it would comply with the laws to put a 5.4 in since the 2000 cobra r had a 5.4. It would be a long time before i did it but i have been wandering about this for a long time.

I did not know this was law, at least not in NYS. For the most part I don't know of a single mechanic that would check for such a thing. All they know is that when they plug in the OBDII scanner for the inspection/emissions, they get good valid data. Doesn't matter what your engine is, as long as you stay with the diagnostic family it's in, they won't notice. You could swap an LS1, 4.6 modular, 5.0 Coyote, and they wouldn't know the difference if it bit them in the face. I don't even think they check the ECM ID code. Hell, you could put an LS1 in a Prius and the majority of them wouldn't know the difference. You might get a "Wow, your Prius is loud. Maybe you need a new muffler."

After all, if that were the case don't you think that'd catch people who swap F150 4.6's into their Mustangs as replacement engines, or replacement ECM's?

However, if you swap an old 5.0 OBDI (or an old non-EFI platform) into an OBDII car, they WILL notice, and Lucy, you'll have some 'splainin to do.

Now this is hearsay, but several of my friends claimed to know this guy who had an insanely built motor with a standalone ECM, which of course had no emissions and was not OBD II compatible. So what did he do for his inspection sticker? Found a friendly shop, and put his old motor in a mount with radiator and gas tank on a trailer. To get the sticker, they'd fire it up and read that ECM, then put the sticker on the built car. Entirely possible, but highly impractical.

And the 5.4TT sounds outrageously badass. One of the guys I bought parts off of had a build in progress. That thing should easily be a 1000+hp monster, and with a 5.4 will have an immensely broad torque curve.