Engines that are common to dodge trucks
THE LA SERIES:273,318,340,360
While the small block is the most popular engine
in Dodge trucks, there is always alot of confusion
about the interchange and differences of the various
small blocks. I would have to say 6 out of every 10
dodge trucks from 72-93 was equipped with a 318 v-8
engine.
While 273's and 340's never came stock in the 72-93 lineage they find their way underhood alot due to
transplants.
The 318 is a very dependable engine and one of the longest production engines of all time. It has a bore and stroke of 3.91x3.31. All cranks are cast internally balanced with the exception of the 67 318 which had a forged crank but was still internally balanced. various measurements are as follows:
main journal:2.50
rod journal: 2.125
pushrod length:7.500 +.015
rod length:6.123
Most 318's utilize a 10.5 clutch and a 10.75 inch converter.
All post 74 318's have a pressed piston pin
The 360 was the biggest of the small blocks and is
closely related to the 318 with some exceptions.
The 360 cranks are all cast externally balanced,
the bore and stroke is 4.00x3.58. The main journal
diameter is increased to 2.81 for added strength.
Rods are the same length as 318.
Pushrod length: 7.515-7.534
Most 360's have 11 converter and 11" clutch.
All 360's use the pressed pin design
The 340 although never installed in a truck from
the factory offers great performance potential if
one is found in reasonable shape.
The 340 shares much of the 318's attributes with
some differences such as:
the 340 bore and stroke is 4.04x3.31
The 340 shares the 318 stroke and the cranks are
interchangeable to a point. The 340 had a forged
crank and internal balance from 68-72. From 72-73
the 340 had a cast externally balanced crank. Care
must be taken when picking a 340 for installation!
The 340 was the only small block to recieve the famed 6bbl package and the 2.02 intake valve heads.
The 273 was the runt of the litter and only should
be looked at to scavenge the adjustable mechanical
valve gear from but I will give some info on it anyway.
Bore and stroke: 3.63x3.31
Crankshaft: Forged and internally balanced
mains: 2.50 rods 2.125
The 340 engine was the only LA to ever see a production six-pack, most small blocks were fitted with a holley 2bbl throught the majority of the 70's. THe 360 4bbl package included the use of the thermoquad carbureator, which was also used for the
first time on the 318 in 1978 as the 318 44bl package, thermoquads were used up to 85 on the small block engines, some 4bbl packages form 79 up came with the Rochester Quadrajet instead of the thermoquad. The late 70's was the high point oddly enough for the 360 engine, the lil red express package was a 360 with 340 cam, carb and intake, producing the enough power to make the Lil Red express truck the fastest accelerating production domestic vehicle in 1978. The other package was the E-58 360, a police car engine that found its way onto the option list of other models, it featured a 340 style intake, better carbureation(richer) and free flowing exhaust. After that things went down hill, in 1979 chrysler introduced EFI on the 318 in the chrysler imperial, making it the the first EFI small block in chrysler history. A few bugs in the system and below average dealership mechanics helped it become a black spot for the small block engine. most 318 efi's were converted to carb and standard ignition once a problem arose. Carbs were here for another 10 years when in 88 we saw throttle body efi arrive on the 318 an in late 89 for the 360. Based on the holley throttle body system but using a chrysler computer, it brought great driveability and gas mileage back tot he LA but they were no land speed rockets by any stretch of the imagination. Something else to mention is that in the 1985/86 production split, the 318 recieved a roller camshaft , the 360 continued using the standard hydraulic stuff until 88 when it to was converted to roller.
SLant six and CUMMINS info will be posted as I get it.
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The B(ig) sereies:350-440
There are really 2 series here separated by block
height and crank stroke, The B and The RB series.
Parts interchangeable between the 2 series:
Heads, exhaust manifolds, camshafts, timing chains,
oil pumps, camshafts and bearings, head gaskets, oil
pans, valve covers(watch out for early 4 bolt covers), rockers, rocker shafts, timing chain covers, fuel pumps, water pumps.
The B series has a lower block than the RB series
and are all related through the crankshaft at a
stroke of 3.375"
Cubic inch differences are made by the bore
CID BORE
350 4.0625
361 4.125
383 4.250
400 4.342
All Crankshafts are forged internally balanced
with exception of late 383's and 74+ 400's
which are cast externally balanced units.
B series measurements:
Mains and rods journals : 2.625 2.38
rod length: 6.538
The RB engine:383(rb),413,426,440
The RB series is a raised block version of the
B engine to accomodate a longer stroke of Crankshaft.
All RB's share the 3.75 inch crankshaft, the same stroked as the 426 hemi, the hemi cranks however use a an 8 boltflywheel instead of the 6 bolt.
CID BORE
383 4.0312
413 4.1875
426 4.2500
440 4.32
The RB has a longer distributor than the b series
and also has a longer rod at 6.768. RB intake manifolds are also wider than the b series, spacers
are availabe to make a b intake fit the rb engine.
All RB's are forged crank internal balance
with the exception of the 70 and up 440's which use
external balanced cranks, the 71-73 440's were forged crank external balance, 74-78 were cast external balance.( flywheels not interchangeable among external balance cast and forged).
Watch for 413,426,440 industrial cranks, they
have a longer end flange than standard cranks,8 holes that are untapped. if your crank flange sticks
out more than .600, you have one of these, unfortunately while a strong crank they have no transmission flywheel application for 72-93 trucks,
they are commonly advertised as 8 bolt hemi race cranks.
Heads: all B/RB can use the same heads, best for
todays gas are the 452's. 906's 915's and 516's
are good heads but lack the hardened exhaust valve seats.
All be engines have used the same basic induction systems over the years, the six pack was only offered on the 440 however and no others. Most b
engines used a carter afb/avs or thermoquad(71+). Some late 60's and eraly 70's used a production holley 4bbl, contrary to popular belief, the holley equipped engines are lo-performance models. The early 4 bbl intakes have small carb patterns, while most 71 up have the thermoquad spreadbore flange. The later thermoquad intakes will usually make more power than the early afb intakes.
In 1972 chrysler pioneered the electronic ignition
system, it found its way into all their engines from this point on. The rb distributor is of course longer than the b.
Something bad also happened in 1972, the rise of unleaded gas and emmissions requirements and the fall of compression ratio's. We saw the end of the performance b as we know it, no more 10.5:1 ratios or six packs, no more magnum cam shafts. Duration of the camshafts for b engines had about 10 degrees of duration cut out of them and about .028 of lift. All B's were changed to a advertised compression ratio of about 8.2:1, to deal with the new poorer quality fuels, and to reduce oxides of nitrogen in the tailpipe. This cost the b engine alot of power. An engine with a large bore like the 400/440 and a low compression ratio makes for a slow lazy burn, and high emmisions, this prompted the introduction of the lean burn system in 74. The lean burn was the fore father to EFI, a computer controlled the spark advance and leaned out the carb to bring emmissions within specs, achieving a mixture ratio of 18:1 to lower gas consumption, unfortunatley the power went south with and 440's were hard pressed to make 200 hp. All of the emmissions equipement and poor performance eventually killed the Big Block in 1978,
which for most of us was really dead since 71. Chryslers failure to improve the big block and to give it a workable EFI system was probably the cause of the corporations dark days in the late 70's early 80's, as the lack of a large motor made chrysler a non player in the truck wars and heavy car market.
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