It is possible to do as long as it isn't to wide to fit in the engine bay. I don't know what is involved with swapping in a manual transmission and making fit. I have swapped the 5.7 in a older 2003 tundra. It is alot of work and took me about 8 months. now if i had all the parts i needed i could have done it in about 3 months. what would worry me is the exhaust hitting the frame.
Sounds awesome... any photos or videos? What did you do for ECU's? Standalone? Transmission?