482 Chevrolet Turbo-Marine

[Lee Stewart]

The parting line on the forging is hand ground smooth the full length of the rod. Areas around the bolt seats are given a generous radius to reduce the potential for stress risers. GM had a design sheet for race preparation of the dimple rod. The Kiekhaefer rods are prepped in identical fashion.
There were 25 of these engines assembled at GM in cooperation with Kiekhaefer. At that time all production Chevy big block packages were designated “Turbo Jet” engines. These development engines were designated 482 Chevrolet “Turbo-Marine” engines even though none were ever turbocharged.

The architecture of packaging a 4.25” stroke into a Std. deck block was much more challenging in the late 60’s, early 70’s than today. There were no aftermarket 4.250” cranks or shelf stock piston pin heights raised .125” or 6.385” connecting rods available at that time. That left two choices for an engine builder. Sourcing a costly custom crank from Moldex or Hank the Crank, or welding and offset grinding a OEM crankshaft, using a Std, piston pin height, a long rod, and a raised deck block. Kiekhaefer , had semi finished rod forgings made that would accommodate the necessary 6.405” c to c length of the rod to package the assembly. The packaging of the assembly is why a tall deck block had to be utilized, in spite of its inherent design disadvantage.
What is a routine 482/489/496 build today, utilizing parts sourced from the aftermarket, was considerably more difficult in 1969.

Block deck dimension Std Deck (454)____ 9.800”
½ stroke/stroke radius_______2.00”
Rod C to C________________6.135”
Piston Compression Ht._____1.645”
Piston to Deck_____________.020”
Total_____________________9.800”


Block deck dimension Tall Deck (482)____ 10.200”
½ stroke/stroke radius_______2.125”
Rod C to C________________6.405”
Piston Compression Ht.______1.645”
Piston to Deck_____________.025”
Total_____________________10.200”

http://www.offshoreonly.com/forums/g...springs-4.html