68 440 Crank pully holes not equally spaced!!!

[zyzzyx]

So today I was measuring my crank and 440 source dampener I.D. to make sure it will fit
when I set my pully on the dampener and kept turning, and turning, and turning, until I
found that one hole from the factory is about 1/8" off. Out the die grinder came and I remedied the situation. The 440 Source bolt hole circle is an even chord, but the pulley
is not. was this done intentionally? I know this **** wasn't made in China! Ha!

 

[R413]

That’s how all of them are made by Chrysler. Approximately 1972 or 1971 and older. The newer ones were symmetrical.

 

[zyzzyx]

So, I know it was bolted to my original harmonic balancer! Must have made them on a Monday.

 

[Dipstick]

'72 was the first year for the symmetric bolt pattern.

Some early engines had the timing mark on the pulley, that's the reason for the asymmetric bolt pattern.

 

[OKDart]

I thought that asymmetrical was for a forged crank damper, and symmetrical was for a cast crank damper. Doesn't matter the year even though most switched over in '73. Due to the thicker mount surface on the damper, the pulleys will line up differently.

Either way, be prepared that your other pulleys might not line up.

 

[Dipstick]

Cast or forged crank makes no difference in the bolt pattern. The only damper that is thick enough to affect pulley spacing is the Street Hemi. Even the bulbous cast crank dampers have the same pulley mounting surface depth as the forged cranks.