When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm a bit confused. You have an '07 with bad engine and trans, and you have an engine and trans from an '09? Are wanting to put the '09 stuff in the '07? But then you mention swapping cabs. Do you have the chassis of the '09, or just the powertrain?
I would just swap the running gear into the '07. Once you start mixing the cab '07 with '09 chassis you'll end up with a mix up of years. If you ever end up selling that could be a nightmare with the titles.