Thanks for posting this. I’m always looking for performance articles on the early 235hp 273’s. I read everything I could find about them during my senior year of high school since I owned a ‘65 Dart Go-go with the four-speed. Wish I could remember what my rear gears were, but they were low (high numerically.) The car would easily hit redline in fourth, resulting in an indicated 115mph, running stock tire sizes. I remember setting up the stock dual-point distributor on my school auto shop Sun machine and adjusting the AVS metering rods to settings published in a magazine. Fuel was 104 octane DX Sunray Super Boron, which was what Sunoco 260 was sold as in Oklahoma. I welded a three-inch cutout just behind the “Y” in the exhaust tubing that exited under the fender. Somewhere I found a set of small-bolt pattern 14” wheels and also a set of “cheater slicks” to mount on them. The stock Auburn three-spring pressure plate didn’t last long under this abuse, so I mounted a rebuilt high-performance disc and pressure plate. Much better. I wish I had kept my timing slips, but my recollection is that the car ran in the high 14’s at our local drag strip. It was a real sleeper, and really stood out amongst all the Mustangs and Camaros.
Makes you wonder what the engine would have done with the original head gaskets. I’m betting that Those other 2hp would have come to the party.
They must have been smaller tube than the stock manifolds.
