Crate engines?

[I make oil]

I'd recommend a crate motor. Pickle the original and put it away. You never know when you might want to sell or restore it to original. In my opinion the EFI's just don't look right in a classic Mustang. If you want FI I'd go with one of the modern bolt ons. I'm installing a carb. I might go to FI later but I doubt it.

If your planning on using the car as a daily driver I'd recommend upgrading to a T-5 transmission if it's a standard or a transmission with a overdrive if it's an auto. Install a 8.8 rear diff out of a Explorer with 3.73 gears and it will be an excellent daily driver. Cool thing about the 8.8 is you also get rear disc brakes with it. I don't think you will need to narrow it for a '68. Be reall careful when you start a project like this. It's real easy to go overboard.