Tech Tips: 1965-'68 Shelby Mustang GT350

[Editor's Note: This article first appeared in our September 2017 issue. Some information and pricing may be different.]

Shelby’s transformation of the Mustang is the stuff of legend. When it comes to making it even better, Cobra Automotive has answers.

Expert: Curt Vogt

Cobra Automotive
(203) 284-3863

First or Second Generation?

The early 1965–’66 Mustangs and Shelbys have historically been more popular for restorers, but lately the 1967–’68 second-generation Shelbys have hit their stride. I think they’re a prettier design, but they are harder to restore. The later cars have a lot more fiberglass body panels, and even when they were new there were plenty of wavy panels and mismatched paint. The bodies were painted in enamel at the Ford plant and shipped to California, where the fiberglass portions-painted with lacquer–were bolted on. It was a recipe for lots of warranty claims then and a lot of restoration headaches now. The later cars also have a much fancier interior-and that Deluxe interior trim is a little harder to restore correctly.

Trick Ponies

All the shiny and trick new stuff isn’t the answer. We’ve done concours and hold track records at race tracks around the country using nearly stock suspension components. It’s a common misunderstanding that Mustangs don’t handle in stock form, but we vintage race and have to use factory-type suspension components, and they work just fine. The real trick is to make sure that you’re using new-old-stock-equivalent suspension components, not some of the new stuff available that’s made overseas. For example, many of the new control arms that you can buy have pressed-in ball joints, not spot-welded or riveted ones. That’s a recipe for disaster on the track.

Ride 'Em Cowboy

To make our cars handle, we’ve got a pretty simple recipe: Koni shocks like the Shelbys originally came with, slightly larger anti-roll bars, and high-quality urethane bushings. I also add shackles to the rear leaf springs to firm up the handling. Personally, I don’t like the feel of the rack-and-pinion conversions. They seem to transmit a lot of vibrations to the driver and tend to be oversensitive to road irregularities.


The nickname Rustang came about for a reason. The unibody construction was manufactured with a lot of overlapping body panels that were spot-welded together. Those lap joints are breeding grounds for rust, especially when salt spray gets trapped in those crevices. Rust in the rear quarter panels, doors and front fenders is pretty common, but steer clear of cars that have rust in the front and rear frame rails. You really have a bad car when the rust gets to the front frame rails and shock towers. There’s a cavity below the upper A-arm in the frame rail tray area that is particularly difficult to fix.

New Old Stock

While it seems as though you can buy just about any part for a Mustang new off the shelf-including complete unibodies–there’s a big problem with quality from some of the manufacturers. Reproduction exterior panels are typically low quality. Instead you should look for new-old-stock parts or, at the very least, parts that were manufactured on the original Ford tooling. Of course, NOS parts aren’t cheap.

A good Shelby restoration deserves a NOS tray. Dynacorn’s more recent replacement body panels are an exception to this rule. Since they’re building complete bodies, they’ve had to be more careful about creating panels that fit correctly without needing a bunch of metal work to line up to the surrounding portions of the car. That translates into better parts for a restoration as well. Reproduction windshield trim pieces are particularly bad. They typically use a softer material that doesn’t retain its shape.


Sealing up windshields is another problem area. A combination of thinner replacement windshield glass and low-quality seals will make for a leaking windshield every time. Thankfully, there are some good seal manufacturers out there–Steele Rubber Products, for example.

Whoa, Pony!

To make our Mustangs and Shelbys work on track, we upgrade the front brakes to those from the 1967 Thunderbird. That gets us 11.87-inch rotors versus the stock 11.3-inch rotors. The rear drums are sourced from a Ford pickup truck and are 11 inches versus the stock 10-inch drums. 

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