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Discussion Starter #1
When did GM change from the short water pump to the long leg one? Was the crank pulley cast or pressed sheet metal?
 

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Truck engines had cast iron crank pulleys (all truck engines used a short water pump), passenger cars had stamped steel pulleys. Chevy went to the long water pump in 1969.

You really don't want a cast iron pulley because it adds weight to the rotating mass (which is why you pay to have high performance cranks gun drilled and the counter weights shaved to lighten them). The width of the V is also different as the belts were heavier to last a lot longer in constant use. A standard belt will fit in the groove (at the bottom of the V) but won't last long as they will begin to slip very quickly in use (been there, done that).

Big Dave
 

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Corvette kept a short water pump up through 1974, which was the last year a BBC appeared in a car of any kind ('vettes have always been segregated from passenger cars, which is why I didn't mention them earlier). After that pick-ups and vans were your source of big block engines; as medium duty trucks and buses migrated over to diesel engines in the eighties.
 

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This site has great details on the 1966 Impala 427 engine details.

The L72 427/425HP Engine | Detroit Automotive

To complete the L72 engine package, below are the other unique parts for this engine (Some parts like the 3872444 Bell Housing are not shown because they were shared with the L35 396 and the L36 427/390HP engines):

The crank pulley was cast along with the WP pulley..

Water Pump Pulley - 3864480
Crank Pulley - 3869978 (casting number)




Distributor (non-transistorized) - 1111100
Carburetor Intake Gasket - 3881847
Air Cleaner, Dual Snorkel - 6421970
Air Cleaner Decal, 427 Flag - 3874904
Air Cleaner Decal, Horsepower Banner, TurboJet 425HP - 3880870
Air Cleaner Stud - 3869954
Air Cleaner Vent Elbow - 3868842
Air Cleaner Vent Hose - 3846122
Flame Arrestor - 3849856
Camshaft - 3863143
Pistons (11.0:1) - Standard - 3888342 - 0.030 over - 3888344
Crankshaft - 3869952, Casting # 6223
Oil Pump - 3876868 ( Replaced by 3904826)
Oil Pump Drive Shaft - 3865886
Vacuum Advance - 1115360
Vacuum Advance Tube - 3877640
Intake Manifold Gasket Kit - 3955527 (for Rectangular Port Heads)
Harmonic Balancer - 3860010
Timing Chain Cover - 3975941
Fuel Pump - 6416459 (AC Number 40358)
Fuel Lines - Pump to Tee: 3886151, Tee Block: 3886153, From Tee to Carb: 3886152
Valve Covers (Drippers) - 3877631 (LH), 3877632 (RH)
PCV Valve - 6423438 (CV691C)
PCV Hose - 3871298
PCV Hose Clip (at Base of Carb) - 3846117
Choke Coil - 3887148
Choke Rod - 3885070
Idler Pulley Bracket - 3878226
Water Pump Pulley - 3864480
Crank Pulley - 3869978 (casting number)
Alternator Pulley - 3844100
Alternator Fan - 3843346
Exhaust Pipe (LH) - 3866523
Exhaust Pipe (RH) - 3866524
Muffler (LH) - 3928215
Muffler (RH) - 3884800
Tailpipe (LH) - 3883697
Tailpipe (RH) - 3883698
Tailpipe Hanger (LH) - 3883693
Tailpipe Hanger (RH) - 3883694
Tailpipe Clamps - 1368195
7000 Tachometer (6000 Red Line)- 6412549
 

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Discussion Starter #6
Thx Brickwhite, I had seen that info a couple of months back and forgot to bookmark....
 

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Dave,The last big block in a Corvette was indeed a 454 in 1974 BUT the last Chevy passenger car with a BBC was the 1976 Chevy Caprice/Impala 454 and the last A-body's with 454 was 1975.In 75 you could get a BB Chevelle/Malibu,El Camino or a Monte Carlo all with the 454.
And Doug Marion of PHR and SuperChevy magazine fame (among other things) did a "Last 454" Malibu/Chevelle feature article that lasted for about 12 or more issues.
California emissions regs squashed the BBC 454 much earlier though.
 
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