Gen 1 Camaro Planning

[HerbyJr]

I'm planning out the power train in my 1967 Camaro and thought I'd ask for some thoughts on automatic transmissions. I haven't yet chosen the engine so I'm pretty wide open, but I know I'll be running a modern LS type engine. I want to go with an engine transmission combination that doesn't require a lot of mods to the tunnel if possible. My goal for the car is a pro-touring vehicle that I can auto-cross on occasion. I'm running the stock front sub-frame with Global West upper and lower control arms, along with QA1 shocks. The rear has a full TCI Torque Arm suspension running Ride Tech adjustable coil overs. She's been mini tubbed and a has a Currie built 9" rear end holding 3.89 gears. My goal is to have something with a lot of torque, but still able to run 75-80 on the highway without feeling like I'm about to redline.

Is someone here familiar enough with Gen 1 Camaros to tell me if one of the modern 5 or 6 speed transmissions with overdrive will require tunnel mods to fit into my 67? Minor mods, may be fine, but I'm not looking to rebuild the floor/tunnel.

Any thoughts on what would be a good fit for my goals and the vehicle would be greatly appreciated.