The B Engines: 350, 361, 383, and 400
Thanks to Eddie Hostler and Hemi Andersen, and the Chrysler Engines
by David Zatz
Chrysler Corporation's first V8 engine tapped expertise in creating high-performance airplane motors; it was efficient, durable, powerful, costly, and slow to build. Soon, GM and Ford were selling cheap V8s hand over fist; and Chrysler rushed to design a new series of big-block V8s, ejecting hemispherical heads
and other niceties.
Volume was key. Originally, Chrysler had figured that the next best thing to Hemi was a polyspherical head
- but it turned out those had little, if any, advantage over the wedge design. They added complexity, weight, and bulk, while their lack of a "squish" area restricted compression. Chrysler followed GM with the wedge design.
Before making its own wedge engines, Dodge advertised the polyspherical design.
According to Willem Weertman, later head of Chrysler engine development, creation of the B series of big block V8 engines was led Robert S. Rarey, starting in 1955 - with a deadline of production for the new 1958 large cars. They had to be capable of class-leading power, so Rarey specified the largest space between cylinder centers of any Chrysler engine, ever - 4.8 inches. The basic design allowed for a 3.75 inch stroke, partly by having both a low-deck block (the LB series, usually just called "B," with a top deck around 10 inches high) and a raised deck block (the RB series, with a 10.725 inch top deck height).
Source: Chrysler Engines, by Willem Weertman
|Used by ||DeSoto||Plymouth||Dodge and DeSoto|
To prevent flex, they used a deep skirt design and a five-bolt head bolt pattern for each cylinder, rather than the old four bolt setup, with five main bearings. At the same time, they tried to reduce weight, using short exhaust ports (which also cut heat rejection to the antifreeze) and side-by-side intake ports (1.95 inches in diameter in 1958; the exhaust port was 1.6 inches).
Past V8s had the oil pump and distributor in the rear of the engine; now, they went up front, to make clearance easier. The oil pump had a die-cast cover that also mounted the spin-on filter. Engineers tried to prevent steam pockets in the water jacket design, and let oil from the valve rockers flow directly into the tappet chamber into the sump, without drilled drain holes in the head or block.
The new engine used stamped steel rocker arms, which Weertman called "unprecedented;" they started with flat steel stock rather than machining it. They also had hydraulic tappets, to avoid the need for regular adjustments (most of the original Hemis had used hydraulic tappets, too).
The "B" series wedge engines were launched in the 1958 cars, just seven years after the original Chrysler V8. Compared to the Hemi and Poly engines, it was light, simple, and cheap to build, yet still tough and sturdy.
For this one year, they were produced in 350 and 361 cubic inch versions, both large-bore, short-stroke designs, with 10:1 compression and identical valve diameters; the Plymouth dual-four-barrel version had a unique camshaft, but the DeSoto two and four barrel versions shared a cam. Made in a newly repurposed plant, they started rolling off the line just in time for the 1958 cars.
From the start, Plymouth, Dodge, and DeSoto shared the B-engine; Chrysler joined in a year later. This was part of a decision to have a single corporate engineering department for engines, after a bewildering variety of parts were created by the divisions as each produced a similar, but different, first-generation V8 engine with the same basic features.
Both the 350 and 361 had a fuel injected version in 1958 only
. Very few "fuelies" were made, and precious few remain, since most had carburetors fitted.
The smallest, least potent B engine, the 1958 350 two-barrel - a one-year wonder used only by DeSoto - was rated at 280 horsepower and 380 pound-feet of torque, roughly matching the 1957 Plymouth Fury's 318 V8 (290 hp, 325 pound-feet), equipped with two
four-barrel carburetors. That was a good sign.
The Plymouth 350 four-barrel had 305 hp; the DeSoto Turboflash produced up to 295 hp; and the Dodge D-500
, went up to 320 hp. The closely related 361 four-barrel, meanwhile, hit 305 horsepower and 400 pound-feet. This engine would last for many years, used in trucks long after the cars had moved on.
B engines were designed from the start to handle ever-increasing amounts of power, with drop-forged steel connecting rods and a forged crankshaft. Maintenance and repair were eased by the external oil pump, dry intake, and front-mounted distributor, along with an easily changed water pump.
Plymouth versions were called Golden Commando and Sonoramic Commando
; Dodge versions, Super Red Ram (formerly used with the Hemi name) and D-500; DeSoto versions (starting in 1959), TurboFlash. These names were not necessarily used by anyone but marketers, but were, in some cases, emblazoned on the valve covers.
In 1959, the 361 was bored out, creating the most common Mopar performance engine for the next decade: the 383. The big bore allowed for larger (2.08") intake valves, and the relatively short stroke helped it to be a free-revving engine as well as a free-breathing one. It launched on the 1959 DeSoto and Dodge cars. This first-year 383 had the same cam timing as the 1958-59 350 and 361 (except the Plymouth Fury version).
|Carburetor||2 barrel||2 barrel|
The DeSoto two-barrel version of the new 383 provided 305 horsepower and 410 pound-feet of torque, an inauspicious beginning. The four-barrel version, coded D-500 by Dodge for that year, was rated at 320 horsepower. DeSoto's four-barrel (standard on the Fireflight) had an extra five horsepower and an extra five pound-feet, at least according to advertising; there may not have been any actual difference.
There was, though, a new attraction for the 1960 cars: a dual-four barrel version of the 361 and 383, with a long cross-ram setup
The first major performance engine in the B series was the 1960 dual-carburetor D500 ram induction package, bringing up to 330 hp and 460 pound-feet of torque; it used a "cross-ram" manifold (the carburetors were on opposite sides of the engine from the cylinders they fed, crossing the valley, to gain the required tube length).
The tubes had an internal length of 30 inches at first, for an added boost while passing on the highway; this was altered to 15 inches later, in some engines, for racing purposes.
The compression ratios for the 361 were dropped from 10:1 to 9:1, for the 1961 cars, so owners could switch to regular fuel instead of premium. Power dropped somewhat, but the 383 was available for those who wanted more. The four-barrel 361 only lasted to the end of 1962; and the two-barrel was only used in cars through 1966.
|D500 (1)||D500 (2)||Ram-Fire|
|Bore x Stroke||4.12 x 3.38||4.12 x 3.38||4.25 x 3.38||4.25 x 3.38|
|295 @ 4,600||320 ||330 @ 4,800||325 @ 4,600|
|390 @ 2,400||420||460 @ 2,800||425 @ 2,800|
Carburetion in 1961 was supplied by a two barrel Stromberg model WWC carburetor (3-188). This carburetor had a rubber-tipped needle valve in the float bowl, to prevent small dirt particles from causing problems; it had a two-stage set-up jet for good fuel flow at cruising speeds. The 1960 cars gained a three-stage metering rod.
1961 was the first year for the closed crankcase ventilation system used on all cars sold in California, designed to painlessly reduce smog. A flexible tube connected a valve and a specially calibrated carburetor; the carburetor had a fitting just below the throttle blades into which the crankcase vapors were drawn by suction. From here they were drawn into the intake manifold for burning, leaving fewer vapors to be discharged into the atmosphere. All cars now use this system.
Engines did not really have chrome-plated fans, oil filter covers, valve covers, or air cleaner housings.
Just as the 361 had been converted to run on regular gas in 1961, the two-barrel 383 was made compatible with regular gas in the 1965 cars, with compression dropping to 9.2:1. (Later, it would fall further - to 8.7:1 in the 1970 cars, and 8.5:1 a year later - to drop emissions).
In 1966, the truck 361 was rated at 186 horsepower at 4,000 rpm and included induction-hardened crankshaft journals, trimetal main and connecting rod bearings, hydraulic valve lifters, sodium-filled exhaust valves with Roto-Caps, and a chrome-alloy cast-iron block.
A special version of the 383 was created for the 1968 Plymouth Road Runner
; it had heads, intake, camshaft, and exhaust manifolds from the 440
Super Commando. Those changes made it the fastest 383 ever, with 335 horsepower and 425 pound-feet of torque; the engine had a 9.5:1 compression ratio, single four-barrel carburetor, and a dual-snorkel air cleaner... and that was the base
engine. The options were a 440 with three carburetors or a twin four-barrel 426 Hemi. This version of the 383 did not stay exclusive to the Road Runner for long.
Starting in 1970, the 383's peak power started to drop, as compression was lowered to cut back on emissions. The first drop was to 8.7:1 in 1970; then to 8.5:1 in the 1971 cars. The lower compression dropped horsepower ratings - but not nearly as much as changing the way horsepower was measured.
|1971 383 four-barrel|
Net horsepower ratings, adopted in 1972, caused many to think that horsepower took a sudden dive; in reality, horsepower was now measured with the air cleaner, water pump, alternator, muffler, and other "accessories." The transition year, 1971, saw both gross and net numbers published for some engines in 1971 (see the charts).
In 1972, the Trenton Engine plant's "B" line switched to a single new bore size, 4.34 inches, bringing the 383 up to 400 cubic inch
es; compression dropped down to 8.2:1 at the same time. The net
power of this new engine was 190 hp and 310 pound-feet of torque with the two-barrel, and 255/340 with the four-barrel - a decent gain in power over the 1971 383. (Rick Ehrenberg of Mopar Action
wrote that the original idea behind the 400
was to standardize all B and RB
engines with a 4.32" bore; Marketing believed that the 400 would sell better than a 396. Hemi Andersen pointed out that the 360, which had been introduced in 1971, may have been too close to the 383 in displacement; the 400 would provide a better gap.)
The 400 had a ductile iron crankshaft, replacing the forged steel crank; this cut costs but, under normal conditions, was durable enough.
Hemi Andersen wrote that changing the crankshaft also meant the need for an eccentric weight in the harmonic balancer, and the addition of a weight to the torque converter. In short, the engine needed to be externally balanced, while the past B and RB engines did not.
Starting in 1973, exhaust-valve seats were induction-hardened to allow use of lead-free fuels. In the hardening process, seats reach a temperature of 1700°F and are then allowed to air-cool. This hardened the valve seat surfaces to a depth of .05" to .08" which gives them greater resistance to wear than unhardened seats. The addition of the Chrysler electronic ignition system, which had been launched in some 1972 cars, eased maintenance requirements and increased reliability.
From 1973 to 1978, emissions equipment continued to become more complex, as engineers worked minor miracles to get carburetors to work more efficiently under all conditions. Fuel injectors were suggested, according to Allpar interviews, but rejected due to cost (which was most likely far less than the cost of the extra warranty work and lost customers). The 1975 addition of Electronic Lean Burn, the world's first computerized spark advance system, helped somewhat.
Two-barrel 400s were dropped in 1976, by which time their output was 175 hp and 300 pound-feet. In the 1978 cars and trucks, the 400-cubic-inch V-8 engines gained dual concentric throttle return springs in addition to a torsion throttle spring. Like all Chrysler V-8 engines, it gained an adapter so mechanics could use a magnetic probe to set the timing.
The performance aspects of the B and RB engines had faded from 1971 until the last one was produced in August 1978. The last vehicle built with a Chrysler big block was a pickup truck made in 1979.
Mopar B and RB engine parts, and engine identification
Over three million 383 engines were produced through 1971, and over 750,000 440 engines were made, which makes many parts readily available.
Which engine do you have? Check the passenger side of the block, underneath the distributor, for a bit of smooth steel with a number code.
The first line has a letter for the year (D = 1968), followed by three digits for displacement (e.g. 440). The date (month and day) are on a line below, with an HP denoting High Performance where applicable. The tag will be just to the right of the distributor on RB engines. Special information (such as undersize crankshaft) may be next to the engine size.
Most B series engines have parts interchangeability, with a few exceptions. The RB, on the other hand, had a wider intake manifold, larger crankshaft main bearing, and various changes to allow for the longer stroke.
The two 383 engines (by Curtis Redgap)
The Chrysler 383 RB was an odd engine, created because Chrysler wanted a 383 but the factory could only produce enough 383 "B" engines for Dodge, Plymouth, and DeSoto. However, the new RB assembly line was under-used; so an RB 383 was created, in two and four barrel versions, for two years. When capacity constraints were removed, the RB 383 was replaced by the "normal" 383.
|Low Block||4.06||3.38||350||High Block||4.18||3.75||413|