L67 top swap...sort of a double...

I own a 99 GT and I want to do a double swap. My girlfriend may be buying a 97 gtp and she wants the better milage of a gt and I would like more power. So I would like to swap the two as mine is a coupe and hers would be a sedan. I found a like to a top swap guide but it never took me to the post, it only brings me to the home page. So if i can get some info that would be great! also has anyone done a double swap like this?

I see that this is your first post, so... First off, Welcome to the forum.

I would advise swapping engines, wiring harness and PCM rather than doing a topswap. It would take less time and you wouldn't have to replace all the gaskets (Given that they don't already need replaced).

Also your fuel mileage information isn't exactly as big of a difference as you're making it to be
3.8L Natually Aspirated is 17 City, 27 Highway and 20 combined
3.8L Supercharged is 16 City. 29 Highway, and 19 combined
That information is referenced for a 2003 model from



Also, if she hasn't already got a 97, advise highly against it due to differences between 97 and 98-03 vehicles including vacuum tree, and transmission.