The Novak Guide to the
Chrysler / Dodge / Mopar Small Block V8 Engine
Mopar Engine History
The Mopar Small Block V8
It is fair to say the Mopar V8 engines represent the "underground" of the muscle era, drawing some of the most devoted conoisseurs of pure power out there. While Chevy and Ford got much of the press, Chryslers motors were developing much of the power. Employing innovative designs and good engineering, Mopar engines have a great history. However, for the discussion of Jeeps, we'll stick with the milder, more sensible swap choices, namely the 318 and 360's.
Jeepers are usually looking for solid torque, reliability, fit and buildability. Do what you will with your Mopar V8, but in stock form, they can make a good Jeep powerplant.
The first 318 engines were built from 1956 to 1966 and are part of the Mopar "A" family, and are not the same as the "LA" block family (318 &360) to follow in 1964 to 2003 and these are the engines of our focus.
At only 25" wide (valve cover to valve cover), the Mopar Small Block is 1" narrower than the Chevy V8. At 29.5", they are 2" longer than the Chevy counterpart, but the same length as the AMC V8's often found in Jeeps. At 550 lbs, the Mopars beat some of the conventional Chevy V8 by 25 lbs.
The length of the 318/360 restricts them to 1972 and later Short Wheelbase Jeeps, but most years of trucks accept them well. The rear-mounted distributor is something for the installer to keep an eye on, but is hardly a hindrance in most installations. The longer water pumps on the engines contribute to the overall length of the motor, and care should be taken to allow for this. Use of conventional mechanical and electrical fans is feasable.
The LA engine's first displacement was 273 c.i. This new lightweight engine was the product of a very innovative casting method. In 1967, a factory 273 V8 passed the "one-for-one" level, reaching 275 hp. In 1967 the 231 was introduced as a two-barrel version, seeing service mainly in trucks. It would not see a four-barrel carburetor until 1978.
The 318 and 360 engines are essentially from the same engine block, but have different heads
Advancing
Fuel injection actually arrived quite early on the FA engines in 1981 through 1983 as throttle-body injection. It was available only on the Chrysler Imperial car, while the carbureted versions continued to be offered on the trucks.
A refreshed version of the 318 and 360 appeared in 1988 for the Dodge trucks and vans, featuring electronic TBI injection. These engines were used through 1991.
In 1992, significant changes in the engine design were released, which included not only multi-port sequential fuel injection, but several other advancements in the intakes, heads, rockers, oiling system, rear main oil seal, and balance characteristics; all which further refined these motors. The 318 has seen continuous development, clear through recent years where it found its way under the hoods of not just the Dodge trucks, but also of the ZJ Grand Cherokee as the 5.2 liter engine (an available upgrade from the Jeep 4.0L I6) which realized 220 hp and 285 ft. lbs of torque.
In 1998, the 360 (5.9L) engine made its way into the ZJ Limited and with that, 245 hp and 335 ft lbs. of torque - enough to propel the Grand Cherokee to a sub-8 second 0-60 time. Not bad. It only took a couple of decades of ambitious mechanics installing V8's into Jeeps to finally revive Chrysler's interest in Jeep muscle. The 5.2 and 5.9 were good motors for the task.
Other Mopar V8's
It should be noted here that the Dodge 3.9L engine is an outgrowth from the 318, much the same as the Buick and Chevy V6's were mechanically related offshoots of their respective "big brother" V8's. The 3.9 has the great power and reliability characteristics as does the V8, but in a more compact package.
Among the newer Mopar V8's that replaced the LA V8's were the Powertech 4.7L overhead cam engine (1999-2009) and the Hemi V8 (2003- ). These engines are not related in components or engineering to the LA V8 family, though they may use the same "Magnum" moniker. Like both GM and Ford had discovered with their similarly famous and long-running small block engines, Chrysler engineers recognized that continuous design improvements to the older LA platform were helpful, but not fully adequate, and that technological advancement was going to outrun them. As such, the LA engines persisted in Dodge trucks and vans up through 2002, where they were replaced by the new Hemi series motors, which were redesigned entirely from the ground, up.
For a better mechanical, history of these fine engines, hit the books. Our job here is to discuss how the motors fit and work in Jeep conversion situations.
Chrysler Small Block Conversions in Jeeps
Engine Mounts
Our #MMX motor mounts for Dodge 318 and 360 engines into Jeep vehicles. Their excellent design allows for the proper placement into nearly every model of Jeep made after 1971. See our engine mounts page for details.
Transmission Options
Where the discussion gets tricky is the area of transmission compatibility. One choice for most Jeeps is the Dodge NP435 transmission, as they bolt readily to these engines, and are adaptable to a variety of Jeep transfer cases. This transmission exhibits all the strength and qualities of the other great truck four-speeds, including great gearing, strength, availability, affordability, and rebuild-ability.
The AX15 transmission is the next option to consider. By obtaining a bellhousing for a Dodge 3.9L V6 as found in the 1996-2002 Dakota trucks, you can marry an AX15 to the Mopar V8. The AX15 has proven to be well matched to V8 power for general street and trail use.
Of course, these engines are also compatible with the 904, 999 and 727Torqueflite transmissions (Dodge patterned only - not AMC), depending on the transmission case castings. For 904 and 999 swaps, these transmissions will require the use of Jeep style transmission to transfer case adapters and output shafts joined to Chrysler cases. Such adapters are difficult to find and not produced by the aftermarket. 727 transmissions do not usually adapt well into some Jeeps due to transmission pan clearance issues.
Exhaust Headers
Sanderson Headers makes these #DD1 block-hugging headers which are likely the best option for many conversion scenarios.
Headers are recommend for nearly all conversions. We carry a set of block hugging headers for the 318 / 360 engines that will fit in nearly any Jeep.
Fuel Delivery
Fuel requirements are dependant more on the era of the engine and its fuel delivery methods. Pressure ranges for them are from 6 to 46 psi, for carbureted to fuel-injected, respectively.
Oil Pans
Many stock 318 & 360's come with a center or front sump oil pan. you should seek out a rear sump pan and dipstick combination. The 318 rear sump pan is a Chrysler #5249062. The 360 takes a #5249060.
Jeep Engine Swap Comparison
We get asked occasionally what our opinions are of the Mopar V8 swaps into Jeeps. Some individuals think they must be easier since Jeep is now a Chrysler company. The swaps are not as intuitive as this would suggest, and on a whole, it is usually going to be easier and more economical to install a GM V8.
318 and 360 swaps into Jeeps are not as well documented as Chevy and Ford V8 swaps, the interest and momentum is rising and a body of knowledge is deepening on the subject. These good engines and worthy of consideration if you have one of these engines on hand. The installer should keep in mind that these engines, while affordable, do generally cost more to install and to work on than the Small Block Chevy and Ford counterparts. For those who understand and are comfortable with these good motors, this is usually not a significant setback.
Summary
Of course, the mechanical history of the Dodge V8 motor is much richer than this synopsis, and we do recommend more research and reading for the enthusiast.
Sources
- The Novak archives and its five+ decades of research and customer input
- Allpar.com