Anyone ever had trouble with the bolt pattern on a Summit balancer?

[bull]

Everything went fine until I tried to install the pulley last night and found that one of the mounting holes is off by half a hole. I double checked it against the original just to make sure I wasn't seeing things and it matches up fine with that one of course. Apparently their machine drilled and tapped it wrong so now I have to rent a puller to remove it and send it back. This is one thing I would not have thought to test fit but obviously I should have.

[lisiecki1]

have you tried rotating the pulley around on the balancer to see if that hole never lines up?  There is one hole that was intentionally drilled different from the others.

atleast on the hemi and my 383 there is...

[Hemidog]

Crank pulleys up to 71 have an offset hole, and the later ones have not.
New pulleys have that hole elongated so they'll fit both.

[FLG]

Yep..later cars had an offset hole. Just elongate the hole on your pulley bull.

[bull]

have you tried rotating the pulley around on the balancer to see if that hole never lines up?  There is one hole that was intentionally drilled different from the others.

atleast on the hemi and my 383 there is...

I rotated it around to every position several times and every time there was one hole that was halfway off center.

Yep..later cars had an offset hole. Just elongate the hole on your pulley bull.

Crank pulleys up to 71 have an offset hole, and the later ones have not.
New pulleys have that hole elongated so they'll fit both.

Hmmm. Interesting. I already called Summit thinking it was their screw up so I'll have to call them back to cancel the swap. I would have never guessed that this would be an issue. Thanks for the help. Time to do some grinding I guess, which is probably better than pulling the balancer back off.

[John_Kunkel]

Yep..later cars had an offset hole. Just elongate the hole on your pulley bull.

Other way around, the earlier had the offset hole; '72 and later are symmetric.

[terrible one]

Yep, had the same thing happen to me. I got the Summit damper too. Saw that something was up and the holes in the damper were all symmetrical . . . but the pulley had an offset hole. Drilled it out and it's all good now. 

[FLG]

Yep..later cars had an offset hole. Just elongate the hole on your pulley bull.

Other way around, the earlier had the offset hole; '72 and later are symmetric.

Brain Fart!

[bull]

So what's a good method of egging the hole out? I was thinking of using one of those straight shank rasp files with an angle grinder but those can be a pain in tight spots.

[General_01]

Dremel tool.