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Mopar Big Block Engine Specifications

Table of Contents:

History
The Mopar big block engines can broken down into 2 groups:
The "B" series engine or Lo-block.
The "RB" series engine or raised (Hi) block.
However, each bore size requires a different block casting.

The "B" series wedge engine was introduced in 1958 in two versions:
350 CID
361 CID
Several years later, by around late 1963, this engine established a reputation for one of the highest performance engines available at the time. In 1964, however, the advent of the 426 CID "Hemi" took the spotlight until 1969 thru '71 when the "B" engine, and "RB" engine as well, came back to the forefront. During these years, the "B' and "RB" engines became one of the most popular high-performance engines ever produced.

Mopar then came out with a new "B" series 383 CID engine. It was brought to the public in 1968. Installed in the Road Runners and Super Bees of that year, it was the largest performance surge to take place in a production car since the early 1960's.

A "B" series 400 CID engine (a 383 CID engine with 4.34 bore) was offered in 1972.

Over 3,000,000 383 CID engines were produced through 1971

Identification marks on the "B" engine are located on the right-hand (passenger) side of the block deck adjacent to the distributor.
Parts replacement information such as undersize crankshaft is located next to the engine size.

Basic Engine Specifications

BORE StrOKE C.I.D.
"B" Engine n/a x 3.38 350
4.12 x 3.38 361
4.25 x 3.38 383
4.34 x 3.38 400

Engine Cylinder Heads

All "B" and "RB" engine cylinder heads are interchangable. The only problem arises in trying to use Stage I, II or III Heads (413-426 Max-Wedge) on the 383 or 400 "B" engine because there is no intake manifold available for this combination.

There have been many "B" engine heads since 1958. The early "B" engine (up to 1961) used a head with 1.95" intake valves and 1.60" exhaust valves. "B" engine heads (up to) 1963 had only four valve cover attaching bolts and used aluminum rocker shaft attaching brackets. The standard 1962 head had a 2.08" intake valve but retained the 1.60" exhaust valve. Several early "B" engine high performance heads, like the 300J Head, used a 2.08" intake valve and a 1.74" exhaust valve. In 1963 and 1964, the six cover attaching bolts and cast-in rocker stands were introduced and are still in use today.

Valve Trains


Valves:
more information forthcoming


Valve Rockers:
more information forthcoming


Push Rods:
more information forthcoming


Valve Lifters:
more information forthcoming


Valve Covers:
All "B" and "RB" engine valve covers are interchangable if not factoring in the positioning of the filler, pcv valve, and other openings.

Below is an incomplete listing of part numbers for custom valve covers from Mopar:

Chrome package P4120609
Blue Anodized aluminum P4286803
Valve cover dress-up package P4120272
Chrome-plated breather cap P4120446
Bottom-vented breather cap P4349046
Valve cover gasket set P4120101


Engine Blocks

Basic Blocks


Crankshaft:
more information forthcoming


Main Bearings:
more information forthcoming

Pistons and Pins:
The 383 CID and 440 CID engines in 1968 uses a piston that is .034" higher in the bore than the 1967's. These pistons installed in a '67 engine will raise it's compression ratio. All 383 CID engines use a 770 gram piston. The 400 uses a 768.5 gram piston.
All "B" and "RB" engines use a 1.09" diameter piston pin which is pressed into the rod.

Domed Pistons for Engines with 11.5:1 Compression Ratio
Mopar Part No's
383 CID Engines
Standard Sized P3690827
.030" Oversized P3690828
.060" Oversized P3690829
400 CID Engines
Standard Sized P3690830
.030" Oversized P3690831
.060" Oversized P3690832
Note: Some of these part numbers have been cancelled.

The above mentioned forged pistons with dome are precision-ground.
To obtain maximum performance from these pistons, they should be fitted as close to .008" clearance as possible as tighter clearances risk piston scuffing.

Click Here for Ring Specifications.
more information forthcoming

Camshaft:
more information forthcoming

Camshaft Specifications

Valve Lash
Cam Kit
No.
 Cam I.D. 
Duration
 Overlap 
Design Lift @ Valve Cam Int. Centerline @ Retainer Int. Ex.
P3690214 Stree Hemi Gr.-108 284 - .471/.474" 106 zero n/a
P3412073 SSH-25-108.5 286 - .485" 108 zero n/a
P3690812 SSH-44-108 292 - .510" 106 zero n/a
P4007277 D.C. Stock "Cheater" 352/380 - .467/.483" 108 zero n/a
P4120235 D.C. 284-108 284 - .484" 108 zero n/a
P4120237 D.C. 292-108 292 n/a .509" 108 zero n/a
P3690816 Stage II-115 300/308 - .518" 110 .028" .032"

Vibration Damper:
more information forthcoming

Timing Chain and Sprockets:
more information forthcoming

Connectin Rods:
more information forthcoming

Connecting Rod Bearings:
more information forthcoming

Oiling:
more information forthcoming


Click Here for Table of Contents


CFM and Manifolds
Manifolds must be sized to match the application. Because manifolds are made for specific engines, select manifolds based on the RPM range.

CFM and Camshafts
With the proper carburetor and manifold, it is possible to select a cam that loses 5% to 15% of the potential HP. These losses come from the wrong lift and duration which try to create air flow that does not match the air flow characteristics of the carburetor, manifold, head and exhaust so volumetric efficiency is reduced. An increase in camshaft lobe duration of 10 degrees will move the HP peak up 500 RPM but watch out, it may lose too much HP at lower RPM.

CFM and Cylinder Heads
Usually, cylinder heads are the limiting component in the whole air flow chain. That is why installing only a large carburetor or a long cam in a stock engine does not work. When it is not possible to replace the cylinder heads because of cost, a better matching carburetor, manifold, cam and exhaust can increase HP of most stock engines by 10 to 15 points. To break 100% Volumetric Efficiency, however, better cylinder heads or OEM “HO” level engines are usually needed.

CFM and Exhaust
An engine must exhaust burned gases before it can intake the next fresh charge. Cast iron, log style manifolds hamper the exhaust process. Tube style exhaust systems are preferred. But headers are often too big, especially for Performer and Performer RPM levels. Improving an engine’s Volumetric Efficiency depends on high exhaust gas velocity to scavenge the cylinder but this will not happen if the exhaust valve dumps into a big header pipe. On the newer computer controlled vehicles it is also important to ensure that all emissions control devices, and especially the O2 sensor, still work as intended.

CFM and Engine Control
Spark timing must be matched to Volumetric Efficiency because VE indicates the quantity and quality of charge in each cylinder on each stroke of the engine. Different engine families require distinctly different spark advance profiles. And even engines of equal CID but different CR require their own unique spark advance profiles.

Expect 0.1% to 0.5% loss in Torque for each 1 degree error in spark timing advanced or retarded from best timing. Also, detonation will occur with spark advanced only 3 degrees to 5 degrees over best timing and detonation will cause 1% to 10% torque loss, immediately, and engine damage if allowed to persist.

Ralph M. Bohm
truckmen@yahoo.com

ICQ UID: #1220946
MSN Messenger ID: ralphbohm@hotmail.com


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Last updated: By Ralph M Bohm
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