Are the moog K7021 and K7023 (sbp disc ball joints) really heavy-duty compared to K785 and K787 (sbp drum)?
If so, is this also true about McQuay-Norris equivalent parts?

I am doing a 10" drum conversion on a 63 Valiant.
Some old posts say that the disc ball joints are stronger - but is that still true? I've read that all manufacturers have reduced the quality of their front end parts compared to old TRW and Moog parts.
I was wondering if they are cutting corners by making one ball joint and drilling the mounting holes 1/2" for drums or 9/16" for disc.

I am going to order from espo, and was going to get the front end kit for 65-72 disc to get the HD lbj and drill out the holes on the drum assy to 9/16".
It would be silly to drill out these holes if the disc and drum parts are identical internally.
I've talked to espo and they don't know.

This was written in 2001:
There were two different pairs of ball joints used on A-bodies:

- upper and lower on 63-76 9" drum, 65-72 10x2.25" drum, 66-72 KH 4 piston discs.

- upper and lower on 73-76 disc and 73-76 10x2.50" drum.

ball joints do not interchange between these two "groupings". i.e. a 76 disc ball joint, upper or lower, could not be used on any year 9" drum brake car.

Almost all 1976 A-bodies were disc brake. There was a federal safety mandate that required discs starting in 1976, however some early production 1976 models may have been produced with drums.

lower ball joints for disc brake cars were heavy duty to accomodate the added unsprung weight of the disc and caliper, however they are the same demension as their drum brake brake counterparts. for example, a 67 disc balljoint can be used on any 9" drum car or a 65-72 10x2.25" drum car as a heavy duty lower ball joint. A 73-76 disc lower ball joint can be used on a 73-76 10x2.50" drum car.

http://slantsix.org/forum/viewtopic.php ... =groupings

There are two 1/2" mounting holes on the spindle for the lower ball joint. One is threaded and one isn't.
Why is one threaded?
If I drilled them out to 9/16, they would both be unthreaded.
Would that be weaker or something?

I have no idea, but this will bump you up.

when i installed KH disks on my valient, I had to drill out the lower bjs to 9/16 because hte bolts would not fit. they have not broken yet, if that helps!

Richard

_________________
63 valient 4 speed over drive, holly 390, dutra duals, power steering, ac, hydraulic roof, KH 4 piston disks, kyb gas adjust all round, sway bars front and rear, 8 3/4 rear axcel and the ugliest green you ever saw

Thanks anyway. I already ordered a standard kit from espo.
The lady was helpful but never heard of the sbp disc lower ball joint being heavy-duty.

A few years ago, when I first started dreaming of doing a front end job, it seemed everybody was saying Moog parts were the best.
The last couple years I've read negative reports on Moog - they're not even made in the same factory or even country sometimes.

I suspect that nowadays (new world order) both the Moog and the McQuay early disc ball joint is just a drum ball joint with larger holes.