A-body. 69 dart with stock K and stock disc spindles ...

.... can I upgrade to a 73 up 16:1 manual box, 73 -76 centerlink and 11/16 tie rods? Any problems? Trying to get better, tighter steering.

Yes.

You would need to also change the pittman arm and the idler arm since the late style center link is flipped over from the early center link. The tie rods will need to be a different length but you should be able to adjust for that.

Thanks

My steering mods are: tubular upper control arms,11/16 tie
rods,reinforced lower control arms,20:1 worm gear.

Firm Feel has a support for the pittman arm and better
option for the idler arm that eliminates the rubber.
I installed those items.

Pretty big improvement.

Mike

This is going back a long time, but I ended up swapping the later K member out of my 75 Duster into my 68 Barracuda to make it work. This was 15-16 years ago, but I think there was an issue with making the idler work Just something to keep your eyes out for.

I believe the idler issues is stud mounting verses through bolt mount. Late 60s is when this change over took place so your '68 idler arm (possible stud mount) may not mount up to the '73 style (through mount) K frame.

I think the conversion from stud to bolt style idler was in 1967. At least it was for the B body cars. So he might be okay. Easy enough to check, just have to open the hood and look down.

Stud ended in 67...

I thought it was '67 but wasn't sure. On a a 42 year old car, anything can be found on occasion and if it is an early production '68, who knows for sure without checking.

Just a follow up on my previous comment. No it isn't/wasn't the stud mounted idler. I was working 6 days a week (on OP cars) and trying to swap parts from the '75 Duster to the '68 Barracuda and get ready to move into my home, i.e going through Escrow hell. SO, I really can't remember the specific issue, but there was an issue that precluded a simple idler/pitman/drag link swap. The 'Cuda was P/S and the M/S box was bought here as an unknown source.

there are two different PITMAN arms depending on manual or power and since your box was unknown source, that may have been what you ran into. The issue was shaft diameter

That sounds very likely

Early a-body power and manual boxes shared the same pitman arm. Some late manual boxes also had the small sector box, but the power boxes were large sector.