Uncle Tony's "New" 383

[Dibbons]

My parents purchased a new '71 Road Runner 383 automatic (see photo of it in present condition back east somewhere). According to Uncle Tony, during that year an automatic 383 had a cast crankshaft and the four-speed had a forged crankshaft (I never heard that before).

 

[Snook]

I don't think so. Look at the balancer. Thick or thin? If thin, forged. If thick, cast. Not iron clad but a good indicator.

Chuck (snook)

 

[RemCharger]

71 2bbls had the cast crank. Coincidently , the would be automatics. Not sure what he has there

 

[w.Hudson]

Nothing is for sure but I haven't seen a 383 with a cast crank and haven't seen a 400 a steel crank.

EVER


LOL

 

[440 PHIXX]

My parents purchased a new '71 Road Runner 383 automatic (see photo of it in present condition back east somewhere). According to Uncle Tony, during that year an automatic 383 had a cast crankshaft and the four-speed had a forged crankshaft (I never heard that before).



View attachment 1829788

He’s correct. Same with the 400 for ‘72 and ‘73. Not sure if that was available in ‘74.

 

[w.Hudson]

71 2bbls had the cast crank. Coincidently , the would be automatics. Not sure what he has there

Correction: I have no experience with a 71 model with a 2bbl

 

[69 Sleeper Bee]

Lets see what AI has to say.
Doesn't mention HP 383's
Don't know if this is accurate or not but I think they were cast cranks at this point.
My Big Block Mopar book states that late in 1971 the 383 2bbl. was given a cast crank.
As @Snook mentioned above a quick look at the harmonic balancer will tell

AI Overview
Learn more

In 1971, Chrysler used a cast crankshaft in the low-performance 383 engines.
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Here's a more detailed explanation:

• Cast Crankshafts:
  In 1971, Chrysler used cast crankshafts in the 383 engines, which were considered a more pedestrian engine in their lineup.
  

• Forged Crankshafts:
  Forged crankshafts are generally stronger than cast crankshafts because the forging process forces the steel to be denser and the grain within the steel to be more uniform, adding to the strength.
  
  
• External Balancing:
  All cast cranks and certain forged steel cranks are externally balanced, requiring specially balanced harmonic dampeners, torque converters, and flywheels.
  
  
• Identifying a Forged Crank:
  A forged crankshaft will have a wide, irregular rough patch on the parting lines on the counterweights.
  
  
• 383 Engine:
  The 383 engine was considered a pedestrian motor in Chrysler's lineup in 1971, soon to be replaced by the 400.
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  I then asked about Chrysler producing a HP383 in 1971
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• AI Overview
  Learn more
  
  Yes, Chrysler continued to produce the 383 engine in 1971, though it was a "pedestrian motor" in the lineup, and was considered by some as a less powerful option compared to other Mopar engines.
  
  
  Here's a more detailed breakdown:
  • 383 as a Big-Block:
    The 383 was a big-block engine, and it was a widely produced performance engine from the sixties through the end of production in 1971.
    
  • Gradual Detuning:
    Like other engines, the 383 was gradually detuned for emissions regulations, and in 1972 it was replaced by the 400.
    
    
  • 383 as a "Pedestrian Motor":
    By 1971, the 383 was considered a less powerful option in Chrysler's lineup, with some seeing it as a "pedestrian motor".
    
    
  • Originally Rated at 335 Horses:
    The 383 was originally rated at 335 horsepower, but a drop in compression for 1971 brought that down to 300.
    
    
  • 383 RB:
    The 383 RB was a variant with a 4+1⁄32 in (102.4 mm; 4.031 in) bore and a 3+3⁄4-inch (95.3 mm) stroke, for a displacement of 382.9 cu in (6,275 cc). It was only available in 1959 and 1960 on the U.S.-built Chrysler Windsors and Saratogas.
    
    
  • 383 B:
    The 383 B engine is not to be confused with the 383 RB
  
  

 

[440 PHIXX]

A guy I worked with had a 400 with the pilot drilled and machined for the bushing. And that was out of a ‘72 Newport. The 4 speed cars got the same forged crankshaft.

 

[w.Hudson]

An old timer always said "You never know what Chrysler would do. You could order cars with several different combinations"

I have had 4 of the 400HP's with the 230 casting blocks. All were cast cranks. The blocks do have distinctive casting font on the blocks.

Craziest thing that I have seen twice is a mid 70's motorhome 440 with a thin balancer and the "Six Pack" rods. Both had steel cranks.

 

[RemCharger]

I've never seen the mythical 400 steel crank, but lots of the 71 383 2bbl cast cranks

 

[w.Hudson]

I also have seen a 73 Road Runner with a 400 and a 4 speed. Even rode in the car once or twice.

The guy who bought it new disassembled it for paint, partially reassembled it and then passed away.
No telling where it is now.

 

[Kern Dog]

Nothing is for sure but I haven't seen a 383 with a cast crank and haven't seen a 400 a steel crank.

EVER


LOL

There were 400 4 speeds built for cars and even trucks.
I have a 440 in a 75 Power Wagon that originally had a 4 speed. It has a forged crank. The 400 4 speeds may have as well.

 

[Dibbons]

From comment section of same video:

"According to the service manuals, the 1971 cast crankshaft was two barrel 383 only and most 1971 383 two barrel engines got forged crankshafts anyway. So maybe late 1971 two barrel only, but not common. In 1972 all 4 barrel 400's got steel cranks and all 2 barrel 400's got cast cranks. For 1973 all automatic 400's got cast cranks and all manual 400's got steel cranks. For 1974 and newer, all 400's got cast cranks, including those with manual transmissions. Cast crank 383's are rare, even with the few 2 barrel 1971 versions and most of those ended up with steel cranks.The 4 barrel 383 had a bigger cam than the 340 horsepower 413. The 1963 and newer 360hp 413 got a new dual pattern cam. Some sources say the 330hp 383 used this cam in 64 and 65, but some say it still used a single pattern cam that was bigger than the 361 and 413 340hp engines. The 66 4 barrel 383 got the then new 440 cam, which was smaller than 65 and rated at 325hp, instead of 330hp. The 2barrel 383 used the smaller 361 cam through 66, but in 67 the 2 barrel 383 got the 350hp 440 cam. In 68 all 383's got 906 heads and even the 2 barrel got a matching high rise 2 barrel intake manifold in 68. The largest 2 barrel carb used on a 383 was the 66 2 barrel, which was larger than the 361 2 barrel, but in 67 the 383 2 barrel got the smaller carb from the 66 361."

 

[Vaanth]

The cast iron crankshaft was introduced in the 383 in 1970 and 1971 in two barrel applications. The following two images show the Technical Service Bulletin (TSB) describing the change:

The 400 engine was formally introduced for the 1972 model year, but a limited number were installed in 1971 Newports as a two barrel.

From Service Highlights for 1972 cars and 1972 trucks:

The crankshaft for the 400 was a carryover from similar 383 applications.


Reference NOTE 2 in the following from the 1972 Passenger Car Parts Catalog regarding 400 engine crankshafts:

Reference the application section for crankshafts used in the 400 in 1972. The forged steel crankshaft # 2268114 is from the 383.

For the following model years, the forged steel crankshaft use in the 400 was phased out. A similar introduction and usage for cast iron crankshafts began in the 1973 model year for 440 engines. The last use of 400 forged steel crankshafts in passenger cars was 1974, typically in manual transmission applications, but were also used in engine numbers 4T400-1-03 through 4T400-1-08, which were two barrel automatic transmission engines. The last use of 440 forged steel crankshafts in passenger cars was 1975. Forged steel crankshafts continued in some Dodge truck applications through 1978, also typically manual transmissions, but most were cast iron.

 

[RemCharger]

Thank you for that. Also of note is the external crank balance is the same for all of those cast cranks

 

[moparedtn]

I just wish they'd have made minor differences in how the harmonic balancer mounts on either type crank so
that they would be definite in identification of cast vs. forged by merely looking at them....

 

[70chall440]

Would not trust anything uncle phony has to say.

 

[cudamark]

Nothing is for sure but I haven't seen a 383 with a cast crank and haven't seen a 400 a steel crank.

EVER


LOL

I've had both. The 400 forged crank is the same one used on the 383 with a forged crank. Same balancer too except for the pulley bolt pattern. The 383 cast crank is the same as the 400 cast crank too.