A 225/60 would fit, since the section width is the
first number: 225mm. That being said, a friend had 235/60R14s on his Charger using its OE 14" road ("Magnum") wheels. They looked pretty small on that car. The "70" or "60" is the expression of sidewall height as a percentage of the section width. P225/70R-14 literally means:
225mm wide, the sidewall is
70% of that width,
R = radial,
14 = rim diameter in inches.
225/25.4 =
8.86" wide (at the
sidewall, not the tread).
225x
70% = 157.5mm sidewall height. 157.5/25.4 = 6.2" sidewall height.
14" + 6.2" + 6.2" =
26.4", the overall diameter of your current tires.
Doing the same math shows a tire OD of 24.6" for a P225/60R-14, and 25.1" for a P235/60R14. So, for
no gain in width by simply switching to a 225/60, you'll lose nearly 2" of tire
height. For the approximate half-inch of overall width (but only about 0.3" of tread) you'd gain by going to a 235/60, you lose 1.3" of height. Height is important--you don't want to have a bunch of unfilled wheelwell. It makes the tires look too small on the car. E-bodies have pretty large wheel openings.
These are P235/60R-14s (25.1" overall height), F/R on my '69 Valiant, with much smaller wheel openings than an E-body:
View attachment 78416
For comparison, here's a P255/50R-17 (27.0" overall height) on my '74 Challenger project:
View attachment 78417
The fender was just hung there temporarily, not aligned, so the wheel's not centered. Regardless, I think losing 2" of overall wheel/tire height would really detract from the look.
The Tire Rack has a really good feature where you can pick a tire, then click on the "Specs" tab, then choose "See specs for all sizes" and it will show you width, overall diameter, acceptable wheel widths, and what size wheel they used to take the measurements (a wider wheel will shorten the height some and a narrower one will make it a tad taller). Click
here to see the specs for all the BFG Radial T/As they carry. Those sizes will be very close to competitor's offerings, such as Cooper, Mastercraft, Kelly, etc.
Another thing to consider when buying tires: How much longer will your chosen size be available? I had the 17" wheels made for my Challenger because, simply put, there are
no good 15" performance tires available in musclecar sizes. 14s and 15s are going away, slowly but surely. I
love the look of Radial T/As--I have a set of 255/60R-15s on steelies/dog dishes for the Challenger--but they're not really comparable to modern performance tires. They're hard, they're slippery... but on the bright side, they last an eternity.