on my 64 cutlass there are two sets of holes for the upper rear control arm, in addition to the two sets of holes there is an additional upper and a lower hole on one side only. So one side has four holes and one has two....

Can someone point me to info about this... Which set should I use, and why are there multiples.... seems like GM didnt just spend money drilling extra holes all over the place for no good reason...

old picture

 

Is that a crack I see in the mount? I would be more worried about that.

 

No cracks...
I did quickly flip through the chassis manual last night and didnt see any mention of the two mounting locations and none of the diagrams show the extra location...

At this point i have no clue which set was in use when i got the car. Im at work now and cant even remember which set I used the other day when i started putting everytihng together

 

So this is a what i see online, but im still looking for actual source material... the second link is talking about 65 cars

The first link implies this was done for a performance benifit, and the second says there were multiple axles offered in the chassis implying they would need a different attachement point

adjustable pinion angle by way of added holes in the frame mounts for the rear upper control arms
https://www.ultimatecarpage.com/foru...gen)-1964-1967

note: 10 bolt rears are in the 3rd hole from the top, 12 bolts are in the 2nd),
https://www.classicautomall.com/vehi...bile-442-coupe

Assuming that either of the above are accurate, I still dont get what the very top and very bottom holes are there for

 

I think Rallye469 was talking about these the other day....heres his pm

https://classicoldsmobile.com/forums...o=newpm&u=6969

 

Thanks..

I sent him a PM and am searching his posts.... i see some photos of the same on the "club coupe period correct 442" thread by olds data.

I never have luck searching on CO and always just use google, im sure this had been discused many times before I just cannot find it..

M

 

Yes…I’m very sure it’s 2nd from bottom- or 3rd one down(where you have it).
Not 100% sure about the other holes or why they were drilled…I’ve also heard a 12 bolt fits the second hole down and 3rd is for the 10 bolt…
But that doesn’t explain the 1st and 4th.
Sorry guys.
-peter

 

Thanks for the confirmation it’s been 20 ish years since I took it all apart

I’ve got the shop warming up now and about to get to work