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.
FIRST YEAR FOR THE CONVERTIBLE SHELBY MUSTANGS
For the first time, buyers could order a convertible version of a Shelby Mustang. Convertible Mustangs were offered from the beginning in 1964 1/2 but it wasn’t until 1968 that a Shelby convertible was available. Like the fastbacks, the Shelby convertibles had a roll bar installed. There were special clips on the top said to be there to help secure a surf board.
THE 68 SHELBY MUSTANGS WERE MODIFIED IN MICHIGAN
The 1968 Shelby GT 350 was a continuation of the ’67 Shelby model. The cars were shipped to AO Smith in Ionia, Michigan from Ford’s assembly plant in Metuchen, New Jersey. Read more about how the Shelby Mustangs ended up being in Michigan instead of California.. click here 1968 Shelby Cobra Story.
The 1967 cars were shipped to Shelby American at the Los Angeles airport for modifications. The cars were built 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.
GONE WAS THE HIPO 289 ENGINE
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 mechanical lifter, Shelby 306 HP version of Hi Po 289. The Shelby version of the new 302 engine was rated at 250 HP. Stock rating for the hydraulic lifter, Ford 302 was 230 HP. There is an internet rumor that the Shelby version of the 302 was some special Mexican block engine. SAAC told me that was not true, that all the small Shelby Mustangs in 1968 got the stock Ford 4 barrel 302.
The Shelby team replaced the stock cast iron intake manifold with an aluminum, Cobra hi-rise, dual plane with a Holley 4 barrel carb setting on top. The intake was manufactured by Offenhauser to Shelby specs. This intake was designed to increase torque at lower RPMs. 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.
JOHN CHUN DESIGNS THE ’68 SHELBY MUSTANGS
Some years ago, i ran into John Chun at a local car show. He walked up to me next to my Shelby. The first thing he said to me was “I designed that car.” I met with John a number of times. He had some great stories. He told me his assignment was to come up with a design for the ’68 cars. And what he proposed needed to be economical. One way to save production costs was to use off the shelf Ford parts. Thus John proposed using 1965 Thunderbird sequential tail lights mounted in a special fiberglass panel across rear of the Mustang body, John gave me copies of his original sketches which are on his pages on this site. Click here to read about John, John Chun – Designer of the 1968 Shelby Cobras.
The factory offered performance and dress up parts like headers, Koni shocks and a unique shift knob. Ram air was standard on the GT 500KR, offered as 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 ’68 GT 350. Note the low restriction 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. Read about the mods I’ve done to the 302 engine, brakes and suspension on my car by clicking here My 1968 Shelby Cobra GT 350.
The Export Brace & Monte Carlo Bar
All the Shelby Mustangs came with a one piece export brace. That is the brace that connects the shock towers to the back of the engine compartment firewall. The US version of the Mustangs came with a two piece brace. Mustangs are unibody cars. The body is the frame. The export brace was used on the Mustangs that were exported. Why? The roads outside the USA were not a smooth as they are here. The export brace added additional strengthening to the front end. All stock Mustangs sold in the US came with a two piece bracing. However, the two piece does not provide the strength that is need and allows the shock towers to come in. If you want to see how much difference the one piece brace makes, go to YouTube, search for installing a one piece export brace and see how difficult it is to replace the two piece with a one piece. There is NO easy way to widen the shock towers. This affects the alignment of the front wheels.
My car also also has an after-market Monte Carlo bar brace across the front of the engine compartment. This bar adds additional strength to the front end. This particular bar is curved to accommodate the oval Cobra air cleaner and give easier access to the distributor. The bar comes as a straight piece as well.
The Monte Carlo bar originated from a brace used on the Falcons that were raced in Europe at Monte Carlo. The unibody Mustang and Falcons bodies tended to flex, especially if driven aggressively. Too much flexing in the front changes the alignment. These two braces tighten up and strengthen the body. Carroll Shelby recommended the Monte Carlo bar for the Falcons. A sidenote: when I got that Monte Carlo bar I had watched some YouTube videos on installing it. Most of the videos had Mustangs with shock towers that had moved in, making it real tough to install this brace. I was expecting it not to fit. However, my Shelby has always had it. That Monte Carlo bar slipped right in place with zero issues. If you happen to own a classic Mustang with the two piece, do yourself a favor to replace it with a one piece.
THE GT 500 SHELBY MUSTANGS
The GT 500’s require a separate page to themselves. Be sure to read about the 1968 Shelby Cobra GT 500 and the GT 500KR King of the Road.
SPECS FOR THE 1968 SHELBY COBRA MUSTANGS
I put together a page with the specifications, measurements and details on the ’68 Shelby Mustangs. I included a column for the current specs on my GT350. Click here to go to that spec page, 1968 Shelby Cobra Specifications
I collected many of the magazine ads for the 1968 Shelby Mustangs, click here, 1968 Shelby Mustang Ads & Brochures.
Production figures for the 1968 Shelby Cobra (Mustangs)
|GT 350 Convertible||404|
|GT 500 Convertible||402|
|GT 500 KR||933|
|GT 500 KR Convertible||318|
|GT 500 Notchback Prototype||1|
|Total Production of 1968 Shelby Mustangs||4,451|
Source of info SAAC – Shelby Automobile Club