Careful with calling the TB trucks extend calibers. They are not compatible with Caliber motor mounts. @marcmt88 makes the proper mounts to fit them though.
Just some slight differences, but I always prefer a snug fit. Had one too many motor mounts come loose on me due to the amount of vibrations and abuse that skateboard trucks take on.
I have my own motor mounts designed and laser cut in aluminum locally, so if my current mounts wouldn’t fit to the TB trucks, I will either modify them with a file and some elbow grease, either design new ones and get them cut.
The Evole GT supercarve trucks WILL work with 6374 motors, but NOT with the Turnigy sk3 “6374” because it’s not actually a 6374. Unless you want to use skinny 9mm belts, I believe there might be a way. But it’s SOOO close I wouldn’t recommend it. For a regular 6374 it should work. I can let you know for sure in a few weeks, I am currently making one