Although the 17x9.5-inch wheels fit on the back of our car, they got pretty close to the rubber bumpstops for the rearend. If we ran the 17s, we'd trim the metal edge on the part of the bumpstop mount that's closest to the wheel, since removing the bumpstops altogether on a regularly driven street car isn't a good idea.
GOING BIG ON SMALLER '65-'66s
Although there are many similarities when it comes to fitting larger wheels on '65-'66 Mustangs as compared to the bigger '67-'73 cars, special considerations are necessary because the earlier cars are smaller in most dimensions. Although they might fit, some believe a fairly large 17-inch wheel-and-tire combo doesn't look right on an early car. In some circumstances, we'd agree.
We have some recommendations for those with a '65 or '66 Mustang. Factory 14-inch wheel-and-tire combinations that came on most '65-'66 cars are fine, but we're going beyond that here. While some might consider it conservative, we think the right 15-inch wheel and tire looks perfect on these smaller Mustangs. For example, the '65 fastback below rides on 15x7-inch Magnum 500 wheels with 225/50R15 tires all around. Now that Vintage Wheel Works offers several 15-inch wheel options, you have an ideal choice for a Vintage 45 in a 15-inch size. Several Mustang parts houses also offer a factory Styled Steel wheel in a 15-inch size that looks cool on a '65 or '66 Mustang. Other tire options include taller 225/60R15s all around or a staggered arrangement with a 215/60R15 up front and 225/60s out back.
As for running 16-inch wheels on '65-'66 Mustangs, you can go with 16x8-inch wheels with 41/2-inch backspacing and 225/50R16 tires all around, or maybe 245/50s in back. That's as big as we'd go, and it's the ideal 16-inch setup for these smaller cars. But fenderwell clearance can be an issue with some cars when trying to run 16-inch wheels in front. For no-hassle fitment on a '65-'66 Mustang, a 15x7-inch wheel with one of the above-mentioned tire sizes is an ideal setup that will look great and won't cause any problems.
Finally, while you can run 17-inch wheels on a '65 or '66 Mustang (and there are many options), be careful because there isn't as much room as on the larger '67-'73 cars. Shop carefully and seek out the advice of a tire/wheel shop or the wheel manufacturer you're working with before going big on an early small Mustang. While it's not impossible, it isn't the norm, so be careful before buying 17-inch wheels and tires for a '65-'66, installing the tires on the wheels, and not being able to return them before realizing they won't fit. Test fit before you mount 17-inch wheels and tires on a '65-'66 Mustang.
"VINTAGE" STYLE
In addition to the three styles of VWW wheels we showed on our '69, there are several other options. Besides the Vintage 45 shown on the car in 16-inch and 17-inch sizes, VWW also offers the Vintage 40, which is the same wheel except for its straight-spoke configuration. That is, if you look at the wheel from the side rather than directly in front of you, you'll notice the spokes are straight across the face of the wheel rather than the gentle curve of the Vintage 45. Shown here are 16- and 17-inch Vintage 40s, which are the same as the 45s in that the 16-inch wheels are one-piece and the 17s are two-piece. Several backspacing options are available for the 17-inch Vintage 40/45 wheels because of their two-piece configuration.
Besides the 40s and 45s, two other styles are available from VWW, one of which is the Shelby 10-spoke-type Vintage 50 shown earlier that's available in 15x7- or 16x8-inch sizes. The other is the Vintage 48, an eight-spoke wheel that looks much like the "Minilite" design--a classic look that's a cool alternative to the equally trick Vintage 40 or 45. The Minilite-style Vintage 48 comes in a 16x8-inch size with 41/2 inches of backspacing. Whether it's a 15-, 16-, or 17-inch wheel, VWW has several offerings, all of which will look great on any classic Mustang, from a restored show car, to a restomodded hot rod, to a worn-in, but not worn-out daily driver like our '69 fastback.
 16x8-inch, one-piece Vintage...  16x8-inch, one-piece Vintage 40. |  17x8-inch, two-piece Vintage...  17x8-inch, two-piece Vintage 40. |  16x8-inch, one-piece Vintage...  16x8-inch, one-piece Vintage 48. |