If you don't mind me adding to this, that arm should be the same for 67,68,69 with drums, Canadian Pontiac and Chev according to the GM parts catalogue.

I saw the disc brake listing, but I didn't think the odds of scrap parts from one of them was too likely!!!

me too! me too!   Do you have info on converting my 66 drum to reg disc?  I have power booster on...  Carl 2

 Thanks for the offer Dave! 
 pm sent.

 Carl2,

 Your best bet would be to obtain a complete 69-70 Impala disc brake setup off ebay. Then refurbish. If you can't find a setup, you could piece it together, but the 69-70 single piston steering arms and caliper brackets are extremely difficult to find on their own.
Everything but the stock rotors and splash shields are dead easy to come by, single piston calipers, pads and bearings and seals are NAPA or Carquest etc.
 Use 69-82 Vette rotors if you can't find the stock ones. Actually, the Vette rotor is far, far cheaper than a stock rotor...if you can even find any, and fits just fine.

You'll need some 69-70 (long) tie rods (at least the outers). Your short 65-66 tie rods won't reach the 67-70 Steering arms geometry, they are more outboard. Some 65-66 guys even adapt on the 67-70 Idler arm, and suggest it changes low speed full lock geometry and elimintes the 65-66 tire squeal.
You'll need 69-82 Vette wheel studs (with the vette rotor), a Disc/Drum master, and a stock 67-70 holdoff valve. Or use a 71 and up Impala (or big GM)combination valve.
Some line work, and you're good to go.

Or... you could go the 69-82 Corvette 4 piston disc brake setup route. It uses the same spindle as the 69-70 Impala but with a different caliper bracket and steering arm. Far easier to find complete as they must have made at least 500k Vettes (I'm figuring anyway) from 69-82. Whereas the 69-70 Impala disc setup was only used for those two years.
Way more HP braking options are available if you go the Vette route. A nice set of slotted and plated rotors with some SSBC Force 10 Aluminum 4 piston calipers...now we're talking! Willwood stuff will even bolt onto the Vette setup.

I'm going to mock up a Vette setup, I'm attempting to see how the 67-70 Impala steering arms fit, and compare them against the Vette arms, geometry wise. There's talk that you need the Impala arm geometry on the big car and the vette arm is different. We'll see.

Cheers, Mark

 The problem with piecing a 69-70 Impala setup together, is finding the elusive single piston steering arms, and splash shields. I've only ever seen the arms by themselves but a couple of times on ebay. I think the same for shields.

Easy to find spindles, and at a good price like you say, and the calipers really are available just about anywhere.

 I got mine off ebay as a complete set as well Dave.
 That's the way to buy it. Try to get it all or most at once. Keep tuned into ebay every day and your horse will come in! 
 And try to get a setup with decent splash shields. Nobody repops them.

Mine were nice, and the spindles were unmarked. Tapered ball joint holes were perfect as well.

Yep,
And you know they'll be a good supply of spindles as such!

Arms found, thanks 69 belair!

If this vette conversion goes as planned, I'll be selling my 69-70 Impala caliper brackets, steering arms and splash shields to anyone interested. They are all in very nice shape. I'll need some cash for a nice pair of new SS sleeved/O ring Delco Morain 4 piston calipers.



Vette Brakes & Products


Cheers, Mark.

lots of the brown coloured ones carl 2, always lots of them.

I have some of these   are they any good?