The small block Shelby Cobra Mustangs.

The 1968 Shelby Mustangs came in two flavors, a small block and a big block. The small block cars were called GT 350. The 1967 GT 350 had the HiPo 289 solid lifter engine. Ford bumped up the displacement in 1968 to 302 engine. Using the same basic block as the earlier 289, the Ford 302 was the next step in the evolution of the Ford small block engine.

The 1968 Shelby GT 350 was a continuation of the ’67 Shelby model. Shipped from Ford’s assembly plant in Metuchen, New Jersey, as Mustang GT’s with heavy duty suspensions, only slight suspension changes were made. The buyers in ’67 demonstrated with their pocketbooks they wanted fewer all out performance options and more luxury features. The suspension changes were special Shelby only coil and leaf springs that became more stiff under stress, yet under normal driving yielded a better ride. The front sway (stabilizer) bar was thicker (.94″) than the GT Mustang and adjustable, Gabriel shock absorbers replaced the GT shocks.

The primary difference, other than the cosmetics, between the ’67 GT 350’s and the ’68 GT 350’s was the engine. Ford discontinued the hi-po 289 after ’67 and introduced the 302.  Gone was the Shelby 306 HP version of Hi Po 289. The Shelby version of the new 302 engine was rated at 250 HP.

Shelby replaced the stock cast iron intake manifold with an aluminum, Cobra hi-rise with a Holley 4 barrel carb setting on top. The very early cars carried the stock cast iron intakes because the factory couldn’t get an ok on the emission tests using the aluminum hi-rise and Holley carb. A unique option offered for the small block version was a Paxton supercharger which increased the horsepower by 40% to about 335 horse. Big block horsepower from a small block Ford. For a few dollars more though, the buyer could get a GT 500, so very few superchargers were actually installed.

The factory offered performance and dress up parts like headers, Koni shocks and shift knobs. Ram air was standard on the GT 500KR, an option on the GT 350. The ram air option was a bonnet that ducted air through the front hood air scoops directly to the air cleaner and carb. It fit under the hood with a cut out for the air cleaner. 

Above is a picture of the engine compartment in my GT 350. Note the oval Cobra air cleaner and the Cobra valve covers. Both were painted black with the silver letters with no paint. the oval air cleaner is the same size as the one used for the dual 4 barrels, although the GT 350 came with a single 4 barrel.  The ’68 Shelby Mustangs had mandatory power steering and power brakes with discs in the front and drums in the rear. My car has an upgraded three core, big block radiator.  

The Shelby Mustangs came with a one piece export brace. The stock Mustang had a two piece. My car has a curved Monte Carlo bar brace across the front of the engine compartment. The unibody Mustang tends to flex especially if driven aggressively. These two braces tighten up and strengthen the body.

The GT 500’s require a separate page to themselves. Be sure to read about the  GT 500’s and the GT 500KR King of the Road.

Production Figures for 1968 Shelby Cobra (Mustangs)
GT 3501,253
GT 350 Convertible404
GT 5001,140
GT 500 Convertible402
GT 500 KR933
GT 500 KR Convertible318
GT 500 Notchback Prototype1
Total Production of 1968 Shelby Mustangs4,451