Holy Hot Rod Horsepower, ‘Stang Man!

By Steel Trap on January 8, 2016

She’s lookin’ good and riding even better!

After reading a tech article in a recent issue of Hot Rod magazine, we got inspired to once again revisit the breathing apparatus on our 1966 Ford Mustang GT Coupe.

Long ago, we replaced the worn out 289 with a 302 and a mild RV cam. Believe it or not, performance was better in the 289 thanks to the longer stroke and a wild cam. So, when we heard a 1/2″ phenolic spacer could actually see gains of up upwards of 30 horsepower, we had to try it for ourselves.

Here it is! The 1/2″ phenolic carb spacer we bought ourselves for Christmas for just $30. With the right setup, such as headers, aluminum intake, heads and performance carb, 20-30 horsepower is attainable.

Here’s a simple project which reaps big rewards with little time invested and for under $50. We literally did the whole thing while the wifey was getting ready and had the ‘Stang running by the time she was ready to roll.

Firstly, you’ll need to ensure your carb and air cleaner will clear the hood area. So, a test fit is in order once you get the part. We ordered ours from a parts place in Michigan, but Jeg’s, Summit or your local speed shop should carry a varied assortment. The good news for us was, with the Shelby GT350 hood, clearance would not be an issue.

The next step is to back out the existing carb stud bolts and replace them with ones for either a half inch or an inch carb spacer. Mr. Gasket has a kit for this, and we bought their 1″ spacer complete install kit at Pep Boys. Later, we may install the 1″ spacer to compare and contrast, though Hot Rod claimed the additional horsepower gains were nominal and only at high rpm.

To back out each carburetor stud bolt, use two of your existing carb stud nuts and tighten them against each other on the intended stud bolt. Then, using a deep socket wrench, loosen the stud and back it out. Installation is the reverse of removal. We’d like to thank Steve’s AutoPro of Hendersonville, Tenn., for this tip!

We replaced this rubber carb gasket with the provided paper one since a corner of it had broken off.

Be sure to put a new, paper carb gasket over the studs first. Then add the spacer and another paper gasket. The spacer itself can only be put on with equal force at all four corners, so you may have to wrangle with it a bit over the taller stud bolts.

Lastly, replace the carb, hook up all fuel and vacuum lines and the linkage and tighten down the nuts. Now, you’re ready to roll!