I had a 56 ACE. I bought it in DEC of 71 in Cal. It had already been repowered with an aluminum 215 cu.in. Oldsmobile V8 Cu. in. OLds , Pontiac, Buick each offered similar engines. Mine had the GM style distributer in front like a Ford. No hood scoop, flat windshield, no side louvers, drum brakes, Saulsberry rear differential IRS , 16 spline drive wheels. The frame flexed, the body cracked. The gas tank was relocated up and into the trunk and had rust scale in it. It had old narrow tires, Muncy 4spd trans, no side curtains or heater. But I used it as an everyday driver for 6 years in IOWA and western WASHINGTON STATE It was fun but not that comfortable. In the winters snow went in one side window and out the side. You couldn't lock it ,rain got in and puddled on the floor, breaking into a onramp the water went to the side and up by my feet, on the gas and the water went behind me. The new 15 in spline drive MG wheels were getting the splines worn over. The rear diff was a great pain to remove the side axle shafts with limited access room for wrenching while replacing
oil seals. But it still was some fun, until a rear axle broke in 77. I didn't know any body or have resources to get it fixed quickly. Family situation pointed to ward a Toyota truck as the next move.
The ACE went to a great new home . Joe found out lots of information, what to do where to go, who had what , and fixed everything. The fix for the twisting frame was uncap the frame tubes and drive precision tubing inside , plug weld the original frame tube to the new precision tubing inside and at the ends and re cap the ends of the original frame tubes and at the ends. That fixed the flexing frame problem. JOE already had a 289 HI-Po engine in his shed when he bought it from me. Joe traded the 215 engine for powder coating the Ace frame. He later sent the car to Arizona and had a craftsman make a 289 Cobra front end body and then replace it, refitted the rear wheels body area and so on to resemble a 289 slab side . He replaced the suspension with Cobra parts from HI-TECH out of TEMPE ARIZONA to include a converted 9" Ford rear IRS and disc brakes all the way around and so on. WA state changed the law after I sold it to Joe about registering replicas and his ACE is already registered as a 56 ACE in WA. state. I know it isn't a true ACE any longer and not an original Shelby either, but still a way better car than it was, Its now dependable and even more fun to drive. As a mechanic I see the value of the changes. As Shelby said " historically warranted modifications"