Comparing Mopars in general to the Rustclang is a bit of a mis-match. A Mustink has little in common with an Imperial. However, that said, A-bodies as a group would be more comparable to the mustang than Mopars in total.
Advantage Mopar
In 1960, NASCAR thought it would be a good idea to race the new compact cars against each other. The 'Stang didn't come out until 64, but it's progenitor, the Falcon, suited up for battle. It's a fair comparison because the Falcon had the same chassis and power plant that was standard issue for the '64 'Stang. The Falcon and Valiant had 170 CID engines and Corvairs had 145. In the field were 8 Valiants, which finished 1-8. NASCAR tried again the next year with similar results. NASCAR would not offer a smaller car series until 1969 responding to the SCCA's TransAm series that was in its glory days.
Current NHRA SuperStock record holder is a clone of the '68 SuperStock Barracuda.
Virtually all currently competing Top Fuel dragsters and Funny cars use engines that follow the design of the Chrysler Hemi. The competing 427 SOHC engine was never installed in a street legal Mustang. Chrysler contracted with Hurst to produce approximately 150 Hemi Darts and Barracudas. Although the intent was to sell these Hemi cars to racers, some did make it onto the street. To their credit, they had very Spartan, but complete interiors.
The attention to details on the Mopars was better than on the 'Stangs. On the early 'Stangs, the door handles were open on the back side. The Mopar door handle was a better quality piece because the handle was full enclosed. It went on into the interior. The seat cushions on the Mopar were thicker and better shaped.
The Mustang used a coil/shock assembly that mounted in a tower. The chassis were particularly flexible, so racers often had braces running from the cowl to the coil tower. Outside of shims, stretching, or cutting the spring, there was no way to raise or lower the front end height. The Mopars could be adjusted by turning a screw on the lower control arm. It was/is a solid system.
1967 was the year that Mopar officially put a big block engine in the A-body and the first year that Phord put a big block in the Mustang. The Mopar 383 was a tight fit and would not allow power steering to be fitted. Maintenance functions were reasonably straight forward to perform.
To tune up a 67 390 Mustang, it was necessary to disconnect the driver's side engine mount and jack up the engine to reach the #7 plug. If power brakes were fitted (i.e. disc brakes), the master cylinder had to be removed to reach the plug. The brakes needed to be bled before turning the car over to the owner.
Mopar used an asymetrical leaf spring system in the rear. This system used the forward part of the spring to locate the axle and the rear part to provide the "springiness". The Mustang had a symmetrical spring that had both ends of the spring doing the same thing. The early Rustclang in particular would develop serious axle tramp under hard acceleration and braking. The Mopars were much more stable.
In order to get the pony to put out decently, it needed the attention of Shelby American, Inc. Without the Shelby influence, the Mustink was not the quality or pleasurable car that Mopar churned out.
Top Engines
First Generation Mustang: 220 hp 289 CID, 271 hp 289 CID
First Generation A-body: 235 hp 273 CID
Second Generation Mustang:
1967: 271 hp 289 CID, 320 hp 390 CID
Second Generation Mopar:
1967: 235 hp 273 CID, 290 hp 383 CID
Second Generation Mustang
1968: 335 hp 428 CID, 360 hp 427 CID
Second Generation Mopar:
1968: 275 hp, 340 CID, 320 hp 383 CID, 515 hp 426 CID * 2x4 Race Hemi
In 1969 and 1970 the horsepower continued to escalate. These model years for Ford are considered third generation cars. There were some interesting engine options on both sides. For 1969 Ford introduced the Boss 302 (290 hp), a 300 hp 351 CID, 375 hp Boss 429. Interestingly, Ford contracted with Kar Kraft to build the Boss 302 and Boss 429 Mustangs. The horsepower ratings given by the factory were notoriously understated on the "Boss" cars.
The 1969 model year line up was the same as 1968. In 1970, the Barracuda moved to the E-body which was significantly larger. The Mustang caught up with the E-body size in 1971. On the engine front, Mopar was no less creative, placing a 440 4bbl (375 hp) in the Dart or a 340 with 3-2bbl carburetors (290 hp) in the 1970 model Duster. Both cars at the instigation of Norm Kraus of Chicago, IL. The 340 was also under-rated.
Horsepower rating notes: While the first generation Mustang seems to have a power advantage with the 271 hp, 289 CID; it's more of a paper advantage. The engine did not work well with the automatic transmission and could be trounced by the 235/273 combination. The four speed cars were comparable performers.
Late in the 60s, lawyers masquarading as safety experts (see Ralph Nader and Joan Claybrook) along with the insurance companies worked tirelessly to put legislation before Congress to increase its regulation of the automotive industry. Insurance companies exerted their considerable influence to reduce the desirability of high performance cars to the auto manufacturers target market by increasing premiums and/or slapping surcharges on anything they deemed "dangerous". To wit: A single male under 25 would pay double the rate of a single female under 25. This would double and quadruple for anything considered today to be a
muscle car.
American manufacturers were targeted by this effort. In response, auto manufacturers would understate the power of the engines. Some figures were outright falsehood, still others stated a power rating at a particular engine RPM. A owner could obtain better performance by simply operating the engine beyond the stated RPM up to maximum RPM recommended by the manufacturer.
