I've done restorations on 2 66 Darts; 273-2V, 3 spd, drums, 270; 273-4V, 904, disks, GT. In the standard Chrysler catalog, the /6 and V-8 cars are listed as two separate models for ordering and production purposes. The obvious differences besides the engines are the radiator, transmission bell housing, springs, and brakes. The 273-2V I had used the same clutch as the /6.
The /6 cars got 9" brakes, the V-8 cars got ten inch brakes as standard equipment. HD brakes were available on the /6 cars which were the 10 inchers.
Disk brakes were available on both models. The master cylinder is different on the disk brake cars. It uses a slightly larger piston. I saw nothing in my research the would exclude the possibility of power brakes with any other brake options. Not saying they aren't there, but I've never seen a '66 A-body MOPAR with power disk brakes.
Both cars had 7¼" open diffs in them. Again, research indicates that the 8.75 was optional. It appears that the 4-speed cars in 1966 had 8.75s standard.
Both the /6 and V-8 models came with 13 inch wheels (except the D/Dart). The D/Dart, cars with disk brakes or GTs with the Rallye package got 14" wheels. The 14" wheels were required to clear the calipers on the disk brake cars and the Goodyear Blue Streak tires only came in 14" sizes. I've seen 4½" wide wheels on disk brake only cars and 5½" on the Rallye package cars (also Formula S Cudas).
The D/Dart was a special beast indeed. Obvious visual clues would be the Holley carburetor and Doug's headers. The factory cars had something like a 4.86:1 gear in the 8.75 diff. A factory news release concerning the D-Dart follows.
Dodge Offers "D" Stock Dart
DETROIT -- A new 275-h.p. Dodge Dart GT that meets D Stock specifications of the NHRA, AHRA and NASCAR is now in production. The "D/Dart" has a shipping weight of 2,946 pounds.
The "D/Dart" features a modified 273-cubic inch engine with a special four-barrel Holley carburetor. Other features include:
A special Camcraft camshaft (284 degrees with .495 intake and .505 exhaust), Racer Brown valve springs, a modified, full-breathing intake manifold, a low-restriction air cleaner, and a Weber clutch. Other standard items are: a heavy-duty 4.86:1 Sure-Grip 8-3/4 inch rear axle, free-flow exhaust headers by Doug of California, a four-speed manual transmission, heavy-duty suspension, and 6.95x14 B.S.W. tires.
The "D/Darts" are regular production line automobiles.
Additionally certain, basic service parts will be available through the Chrysler Parts Division, so that owners of earlier Darts may convert from the 235-h.p. to the new 275-h.p. version of the 273 V-8 engine.
The "D/Dart" has been certified by the sanctioning agencies in the D Stock class. It is expected that this car, properly prepared, will be a top contender.
A high idle speed minimizes roughness, a high numerical axle ratio is used for top acceleration, the distributor is modified for quick advance, and the ignition system is designed for optimum engine output. Due to the expected use of these vehicles, no warranty coverage applies.
Those who are interested in more specific technical details on this car may contact staff engineer Dick Maxwell, Product Planning, Chrysler Corporation, 341 Massachusetts Ave., Detroit 31, Michigan. Phone 313-883-4500, ext. 3947.
In case your local Dodge dealer does not have a full list of the part numbers for these specific components you may wish to contact performance parts specialist Ray Ryder, Chrysler Parts Division, 22631 Lawrence Avenue, Centerline, Michigan. Phone 313-539-3000, ext. 7763
FWIW: The tire profile width of a 6.95-14 is closest to a 175/82-14 in the current measuring system. To get the same load carrying capacity, a 195/82-14 comes closest.
Hope this helps the discussion along.
