Finally, we had the tires. Tiremakers give specs on their tire's overall width, or section width. Our Firestone 255s have a section width of 10 1/2 inches, meaning they'll bulge out 3/4 inch per side from the edge of our new 15x8-inch rims, which have a 9-inch overall width. We now have enough info to bolt up a cop wheel and see if the new setup will fit.

Once the decal is rubbed into...

Once the decal is rubbed into place, the outer backing paper is peeled back. We similarly installed the opposite stripe. The top of the stripe needs to end up exactly the same distance back at the top of the quarter as the opposite side. Theoretically, using the same body line and sidemarker references, the alignment should end up the same. If not, the straight segment across the decklid will be crooked. We measured and marked the distance to make sure the quarter stripes land exactly the same distance back where they meet the trunk. With the side pieces done, all that was left was to join them with the deck segment. We marked the centerline of the deck and stripe, and then pasted it down.

The side marker housings need...

The side marker housings need to be painted to match. We mixed black and flattening base in urethane until we got a good match (10 percent flat base), and sprayed the housings with a touch-up gun.

Rolling Thunder The correct...

Rolling Thunder
The correct tire-and-wheel combo can make the look just as sure as the wrong choice can break it. We shied away from modern billet and trendy large-diameter wheels for a more traditional "'60s race" appearance. We took one look at Wheel Vintique's new "Cruzer" mags and knew that was the wheel for this machine. We had a set of Firestone SS 20 radials mounted blackwall in front. For the rear, the 'Stones were mounted letters out, but we blacked out all but the "Firestone" lettering for that vintage-racer vibe.

The "Cruzer" is available...

The "Cruzer" is available with flanged center caps or spinners. We went with the spinners: a three-piece arrangement with a true knock-off threaded spinner mounting on a bolt-on spindle with a lug cap sandwiched below. Very nice stuff.

The "Cruzer" wheel takes a...

The "Cruzer" wheel takes a tapered seat lugnut. We prefer a large taper nut, like the Dorman #611-093 on the left, rather than the small seat found on typical mag lugnuts (right).

At the rear, we had 15x7 cop...

At the rear, we had 15x7 cop wheels with 235/60-15s, but with the rolled fenderlip on this Dart, we had room for more. We ordered a pair of 15x8-inch rears, which have a centerline offset of 4 1/2-inch backspacing-and they fit like a glove with 255 60-15 tires. It's all tire from leaf spring to outer fenderwell, and perfectly centered on this car. However, that fit is combination-specific. We have tightly rolled fender lip flanges and an A-Body 8 1/4-inch rear with 11x2 1/2-inch B-Body brakes. Different brakes or rears make for a different fit. Mock-up with a known wheel, and see how much distance there is to the inside and outside before ordering wheels and tires.

Up front we went with 15x7s...

Up front we went with 15x7s mounting 235 60-15s. The front fenders on this car had previously been modified for clearance with this size tire. Again, fit is combination-specific, and the front suspension of this Dart had been altered significantly. Check for specific fit on your car.

Wheel Backspacing: Will It...

Wheel Backspacing: Will It Fit?
Backspacing is the distance from the inside-mounting surface of a wheel to the outside edge. Knowing that the difference in backspacing between our new Wheel Vintiques wheels and the old cop rims is plus 1/4-inch, and the difference in overall width is 1 inch, we know the edges of our new wheels will be 1/4 inch farther in and 3/4 inch farther out.

With a cop wheel bolted up,...

With a cop wheel bolted up, we measured to the leaf spring and found slightly over 1 1/4 inch of clearance. The new wheel, with 1/4-inch more backspacing, will give us just over an inch. Since our tire is 10 1/2-inch section width, and the new rim is 9 inches wide overall, the tires will take up 3/4 inch of that clearance, leaving slightly over 1/4 inch to the tire.

On the outside edge, our new...

On the outside edge, our new wheels will be 3/4 inch further out, and the tire will stick out 3/4 inch beyond that. We ran a straight edge up from the old wheel to the previously rolled fenderlip of the Dart, and found over 2 inches, so the new combo will clear the lip. Higher up in the wheelwell, the outer wheelhouse curves inward toward the tire, but the tire gets narrower as it curves from the sidewall toward thread. This is tough to judge and may present an interference problem at full jounce. It looked like the tires would clear and we were prepared to modify the wheelhouse if not.

Up front the job is much more...

Up front the job is much more complicated due to the steering arc. The only way to know what'll fit is to try it, or to have a fit test done at a tire shop with the special equipment. Using the same techniques as for the rear, a pretty good estimation could be made, although we recommend doing the check with the tires installed. Luckily, most people don't feel the need for massive tires up front. We were happy with the 235 60-15 combo on 7-inch cop wheels that we had up front before. The new Wheel Vintiques' 15x7s have a backspacing of 4 inches, so they will be 1/4 inch farther out than the old 4 1/4-inch backspaced cop rims. We had a slight interference problem to the inner fenders before, on full lock turns, so this could only make the fit better. This Dart already had numerous mods made to the suspension, and reradiused front fender corners, so don't use it as a guide for what will fit on your car.