When you get to the tuning part contact Dynocomp in Scottsdale, Az. They were able to successfully tune Hooleyboy's C55 n/a with an E55 SC on the motor. He spent about 12k on the project, but may have overcame a few bugs that might help on your project. Your right on the tranny though. He ended up sending it out to Renntech in Florida to get it fully rebuilt. Good luck on your project.