I am still collecting parts to convert my 72 10" front drums to 73 10" drums. (A-bodies) I have leftover parts from a 73 drum to disc swap plus more.

If I read right, I was assured here that the UCA is the only thing that changed to take the 73 big upper ball joint. If that is true, then the holes in the 72 and 73 knuckles are interchangeable with the holes in the 72 and 73 lower ball joint assembly, right? And the 72 and 73 LBJs both fit on a 72 LCA?

This is pretty easy to swallow if the only change they made in 73 was the big upper ball joint. The thing that nags me is that all the parts suppliers have a different p/n for the 72 LBJ, and it costs WAY more!?

Can someone reassure me before I spend my money? If it really does all interchange could this mark up be a product of the market forces that make the factory service manual more expensive for 72, because it is more of a "high dollar collectable muscle car year"?

Sorry to ask the same question twice, but Im both interested in a more detailed answer and paranoid about spending money for parts I can't use. Can I buy 73 LBJs for my 72 LCAs?

Thanks

Kevin

_________________

madam im adam

In '73 the switch was made to the B-body type lower ball joint and a different spindle. The '73 and newer ball joint is different from the '72 and earlier 10" drum brake ball joint and all the other '72 and earlier lower ball joints.

If your car had 10" drum brakes it should already have the large upper ball joint so the upper control arm should not have to be swapped. If it's a 9" drum brake car it will have the small upper ball joint and the UCA will need to be changed.

The change was the lower ball joint not the upper.

The lower ball joint STUD which fits the lower control arm hole is the same for all the different lower ball joints used. The '73 ball joint therefore fits the earlier lower control arm. It will not, however, bolt to the '72 and earlier spindle.

_________________
Joshua

"If your car had 10" drum brakes it should already have the large upper ball joint so the upper control arm should not have to be swapped. If it's a 9" drum brake car it will have the small upper ball joint and the UCA will need to be changed.

The change was the lower ball joint not the upper"

I have not found this to be the case in my conversions. I've found that all 72 and earlier upper A-arms (that I've dealt with) are of the earlier configuration and must also be swapped for this conversion. Maybe some were phased in ealier, but I haven't seen 'em. All the other facts are dead on!

_________________
. . . there was good sport at his making.

Had a 73 Scamp with 10 in drums and it had the small 72-earlier small upper and lower upper ball joint. Could have been from using leftover 72 parts.

I really needed to know the straight dope.

In other words:

72 LCA can take an early style 72 or late style 73 knuckle, depending on the LBJ which can be swapped through all years A body. Knuckle must match ball Joint style: early or late.

All 9" front brakes take early lower ball joint and knuckle with early style small ball joint UCA.

Possibly excluding early 73 cars which may have used a 10" drum on a knuckle made for early ball joints...


Now I can spend wisely and convert to 73 for strength and economy!

Kevin

_________________

madam im adam

Any A body lower control arm can take any lower ball joint as the ball joint studs are all the same dimension.

Yes, the lower ball joints have to match the spindle. I don't call it a steering knuckle as the steering arm is part of the lower ball joint. Early spindles excepting those for disc brakes and evidently some 10" drums use a smaller upper ball joint with a correspondingly smaller hole in the upper control arm.

My '67 Valiant got the upper control arms, upper and lower ball joints and spindles from a '75 Duster. I changed the lower control arms only because the Duster had sway bar tabs.

_________________
Joshua

I have a 73 scamp, and I've been battling this same question in preparation for a swap to K-H Four pistons! further complicating the issue is my desire to use a set of aftermarket 'drop spindles' from this Aussie company.

http://www.rodshop.com.au/chassis.htm

I'm pretty sure it was decided Aussie chassis parts do not fit our A bodies. You might have to send them a lower ball joint so they can make the spindle to fit.

Why the K-H disc brakes? Also, if you want to get the car really low talk to Dick at Firm Feel.

_________________
Joshua

Really? When? I know there were questions about the Aussie HEMI 6, but I had not heard that about suspension... Perhaps a link, or suggested search keyword?

Is there something about the K-H system that I do not know? Something that has convinced folks to steer clear of them?

As for the drop-spindles; I already backed off my bars, and of course, gained quite a mushy feel while loosing travel... i was thinking that drop spindles would set the car in the weeds and still allow me to keep some tension on the bars...
...haven't been over to the Firm Feel www in a while. Have they added some new products? (I'll go there now)