Large diameter dual pulley?

[SSing]

I´m trying to track down the origin of the large (think 3,5") dual alterator pulley, you find in some of the 60´s race engine applications.
Was it a pulley Chrysler spacifically made for racing? If so why a dual pulley?
Or could we find this pulley on an ordinary production engine, early sixties or late fivties even?
Picture is the 1962 413 cu.in. engine. Think same type pulley was used for the later SS package car.
Thank you.

 

[RemCharger]

Imperials had them.

 

[YY1]

Underdrive?

 

[R413]

Yes for high RPM operation, maximum performance engines, the orange monster, etc.

 

[SSing]

Imperials had them.

Ok, make sense. Thank you.

 

[RJRENTON]

I´m trying to track down the origin of the large (think 3,5") dual alterator pulley, you find in some of the 60´s race engine applications.
Was it a pulley Chrysler spacifically made for racing? If so why a dual pulley?
Or could we find this pulley on an ordinary production engine, early sixties or late fivties even?
Picture is the 1962 413 cu.in. engine. Think same type pulley was used for the later SS package car.
Thank you.
View attachment 1631161

The alternator sheave (aka "pulley") had a slightly smaller pitch diameter to help prevent high RPM operation from throwing the belt off as the belt will ripple and flex.....
BOB RENTON