With a 16" wheel you'd probably be best staying with a 16x7 and 4.25 to 4.5" of backspace. You might be able to get a little more than that but it may end up being dependent on the rim design. A 225 wide tire would still be about the max width, maybe a 235 if you go 4.5" of backspace. With a Barracuda you'll need to keep the height under 26" unless you want to modify the lower front corner of the fender.
With a 17" rim you can go up to a 17x8 and about 5.6" of backspace, after that the outer tie rod end can become an issue. If you keep the backspace between 5.25" and 5.6" anything up to a 245/45/17 should fit pretty easily.
In the back I forgot to ask which rear axle you actually have. If its an A-body width 8 3/4 with BBP axles and disk brakes and the factory spring locations you should be able to fit up a 275 wide tire with the proper backspacing. 16x9 or 17x9, backspace should be around 5.25" to 5.5". If it's not an A-body width 8 3/4 then the backspace would be different.
