New Project but No Experience

Just purchased a convertible '68 Barracuda with a Slant6 as a project car sight-unseen.

Up-front, I am not a mopar specific enthusiast and this will be my first full resto-rod project that a friend (not a mopar guy either) who's done a lot of car project will be taking on with me. Thankfully we have a common close friend who is a mopar fanatic and will help us a great deal, but I'd like to get input from as many people as possible.

I anticipate the Slant6 engine is under-powered and would appreciate people's thoughts on engine alternatives that don't make the car difficult to control or dangerous (e.g. no 440 block for me). Likely will put an automatic transmission with it so my wife will drive it on long trips.

Intending to lower the stance, hot-rod it a bit, use non-traditional mopar paint color, and will put some meat on the rear end (e.g. not taking a "restoration" approach). Might be open to a fuel injected engine and modern transmission too. Appreciate any input people have on the drive train related to balancing power with the reality that burn-outs, fish-tails and street racing are a thing of the past ... but we still sneak it in once-in-a-while !!!