Valiant, Duster, Dart, and other Chrysler A-Bodies: Engines, fixes, tips, and performance modifications
A-body engines included the 198 and 225 six, 273/318/360, 340, and 383). About 50 hemi-Darts were produced for racing (GRay022396@aol.com). With modern technology, the 318 and 360 now generate 230 hp. The 340 was discontinued in the early 1970s, and the 426 Hemi was just put back into production for racing. The slant six reportedly served as the basis for the 2.2/2.5 liter four-cylinder engine.
The slant six was introduced in 1960, having been designed largely for the Valiant and Lancer. The 170, 198, and 225 cid slant six ranged from 101 bhp to 145 bhp (gross hp). A four-barrel carb and hotter intake manifold were available from Offenhauser; and Valiants in South Africa were, for a time, sold with a stock four-barrel pumping out 195 hp (gross).
Australian Valiants had Australia-only 215, 245, and 265 inline six Hemis, based on US truck engines that never saw the light of day; the 265 Charger E49 could run a 14.4 second quarter mile.
The 273 and 318 V-8s were similar designs, and normally had a two barrel carburetor. A four barrel will provide more power. Australian Valiant Chargers and late Dusters could have the 360 as well, a large version of the 318 with a potential for power. The pre-1972 318 had 230 hp and 320 lb-ft of torque (gross), moving to 150 hp (net).
The 340 V-8 was a performance engine which brought the Duster and Dart to great speed. The 340 Duster's handling/performance combination was very hard to beat, especially when price was thrown in.
Dave Gittner wrote that there was an A38 package avail on the 1976 A-bodies with the 360 4-barrel as an option. He sent me a copy of the 1976 police brochure, which I have to condense and add to this page soon. You've already seen the graphics from it.
Keith Fosberg tells us: The Hemi GTS Dart was a "race only" version that was not legal for sale as a street car. I'm not sure about the 440 version, it may have been also. The 383 was available as a normal option for the 68 and 69 Dart. It is not very common however as it cost $1038 on top of the GT package, quite a stiff price for '68! I believe the total production run for both years was under 1000. There are a lot of "fakes" running around, but you can spot them pretty quick by checking the VIN.
Modifications, fixes, and special features
For the 318, some recommend a progressive four-barrel; just don't go overboard!A good four-barrel carb with narrow primaries and wide secondaries may not hurt your mileage. The 318 was used on many police cars, hint. The Mopar Performance catalog suggests the Edelbrock Performer intake manifold.
The 340 and 360 were more performance oriented and are good replacements for the 318.
Many people want to go from the slant six to V-8s, or from small to big V-8s. Here is a part that may help. Others may be interested in this article on engine and carburetor upgrades for the 273, 318, and 360. Weber carburetor upgrades are often lauded.
You may want to take a good look at tires, because the Valiants were built in an era of poor tires. In the 1970s, dealers said optional sway bars were needed to avoid eating radials, but SL6 Dan says this is no longer true due to changes in tire construction. Use a sportier tire than the OEM for better handling - e.g. Yokohama Avid MD-H4, which comes in the standard sizes and is excellent in rain.
In 1967, the base wheels were 4.5 inches wide, 13 inch diameter (in the U.S. Australians had 4.5 x 14 wheels.) In 1969, Australian Valiants had a 5 x 14 wheel (except Regal 770 which had a 5.5 x 14 wheel).
By 1973, the standard Plymouth Valiant-Dodge Dart-Plymouth Duster wheel was 14 inches in diameter; width was 4.5 inches for all but the 340 V8 which got a 5.5 inch width. That specification seems to have remained through 1976, with the 360 V8 getting the larger wheel after the 340 was dropped.
You can tell if the “radial tire roadability package” was installed by the door sticker — if it lists “DR78” or “ER78” then it was probably installed. (The “R” stands for “Radial.”) Wheel sizes were 4.5J and 5.5JJ — the smaller tires could but put onto the larger wheels but not vice versa.
Appropriate modern tires to replace the D78-14 standard tire appear to be 185/75R14. The larger tires can handle 205/70R14 tires.
Slant six to V-8 upgrade
Changes include the K-frame, transmission (different bolt pattern), and radiator. In addition, the suspension should be beefed up, the brakes might not be adequate, and the rear end might also be insufficient to support the additional power.
Steve Lent wrote: " I just finished putting a 318 into a 61 V200. It just bolts in."
1. 1964 Valiant "K" member with steering gear.
2. Engine mounts and "Iron" from Schumacher Engineering
3. Exhaust manifolds from 72-74 318 LA engine
4. Drive shaft will have to be made.
5. Extra heater box (engine side) Modify as necessary to clear dist.
6. 1965-66 Valiant V8 Steering cross link.
The one I built.
- Engine - 1985 New Yorker 5th. Ave.
- Transmission - 1968 904
- Rear end - 1966 Barracuda Formula "S" 8 3/4"
- Front brakes - 1966 Barracuda Formula "S" disks
- Rear brakes - 1966 Barracuda Formula "S" 10" Drums
- Radiator - 1974 Valiant with 318 and A/C (move fill inlet 2" to the right or cut opening in front of hood for clearance.
- Rear cross member will need modification I used a 62 trans. mount and fabricated
a cross member from 10ga. steel to fit.
- I used a 1972 RV2 A/C comp. and under dash Evaporator unit.
- Seats 1986 New Yorker front wheel drive.
Every thing FITS under a STOCK hood.
This is my wife's "grocery getter" My truck is a 1983 Rampage with 1987 2.2 turbo and automatic trans. Again all factory parts used on swaps.