DragStuff

What is the difference between a stock OEM cast crank and an aftermarket cast steel crank?

I always thought an oem cast crank was iron and the aftermarket cast cranks are steel.

THEY ARE !!! GM IS CAST IRON-AFTER MARKET IS CAST STEEL, STEEL IS STRONGER.
MICK

Thanks guys , that is what I thought but a friend was determined there was no difference.

coony278 wrote:Thanks guys , that is what I thought but a friend was determined there was no difference.

Correct me if I'm wrong, but GM produced both cast (iron) and forged (steel) cranks, right ?

A forged steel crank is a forged steel crank, whether it be OEM or aftermarket.

Am I missing something ?

I have copied and pasted a discription of these cranks. At first they are called nodular cast steel. But later at the bottom the material is listed as cast iron. Well, both are sort of correct. The material is actually cast iron but the steel content is higher in the 9000 series than the original OEM casting. Any cast crank is cast iron. Just some are made of different material content. A forged crank is just that, forged. The process uses a forging die that makes a much denser part by compacting the grains and also a better material is used.



Product Description
These brand new 9000 series cast steel cranks are stronger and more durable than OEM castings. This makes Scat 9000 cranks an excellent choice for the budget minded performance enthusiast. These brand new 9000 series cast steel cranks are stronger and more durable than OEM castings. This makes Scat 9000 cranks an excellent choice for the budget minded performance enthusiast.

Precision ground and micro polished.
No more hassles with poor quality crank cores.
Simplify your bearing stocks to all standard/standard size.
Additional Information
Motor Type : SB Chevy

Main Size : 350

Stroke : 3.750

Manufacturer PN : SCT 9-103750

Manufacturer : Scat

Manufacturer Description : SCAT’s commitment to excellence is why our customer base includes such names as Ford Motor Company, Daimler-Chrysler Corp., Toyota Racing Development, Nissan and General Motors. SCAT has been, and continues to be, a force in the performance aftermarket providing crankshafts to many of the country’s top racing teams. From Indy cars to Top Fuel Dragsters to World of Outlaw Sprint Cars and Winston Cup, SCAT always finds a way to the Winners Circle. SCAT also offers a complete line of custom seating systems for Muscle Cars, Hot Rods, Off-road, Sport Compact and VW.

Product Data : Rear Main Seal Style : 2-piece
Main Journal : 350
Engine Stroke (in) : 3.750 in.
Rod Length (in) : 5.700 in.
Crankshaft Material : Cast iron
Engine Balance : External
Lightened : No
Rod Bearings Included : No
Main Bearings Included : No
Rod Journal Diameter (in) : 2.100 in.
Crankshaft Snout Style : Standard
Quantity : Sold individually.

There desription is kinda contradictive isnt it ? So both cranks are cast iron. The after market is just supposedly better material. Hmmm I guess now that my friend must have knowed what he was talking about.

CAST IRON IS CAST IRON.STEEL IS DIFFRENT MEANING IT HAS DIFFRENT ALLOYS IN IT THUS 4340 STEEL CRANKS HAVE DIFFRENT ALLOYS IN IT THAN 4130. BUY 4340 IF YOU CAN AFFORD AND NEVER LOOK BACK

cast is poured, forged is formed under pressure.