what finish was on the smog manifold tubes from factory

[chewychevy67]

Anyone know what finish was used from factory on the A.I.R. tubes that go on the exhaust manifolds. Plating, paint or other? Hopefully something that will stay on for longer than a week. I am going to have my manifolds ceramic coated. Rod.

['68OrangeSunshine]

Although I dumped all my stock Calif. '68 A.I.R. gear in a 50 gallon trash barrel at Cherry Point NC, back in 1974, I seem to recollect it was painted something close to a hi-temp Cast Iron Gray.

[chewychevy67]

yeah I am going to de-vein the pump and block the tubes so that it looks the part but is inoperable.

['68OrangeSunshine]

Well it's your truck, Friend, but if it were my project, I'd dump 45 Lbs of No-Go gear, and those Lo-Perf A.I.R. rams horns, and ceramic coat some good headers.

[chewychevy67]

I am rebuilding stock so no headers. Anyone confirm grey?

[chewychevy67]

Ttt

[Steeveedee]

My recollection is cad plate, but that's from 40 years ago. Maybe check out Team Chevelle. Lots of restoration experts over there. http://www.chevelles.com/forums/

[chewychevy67]

I was hoping it would be something more resistant to heat. my plating guy says that cad will discolour first start up. Any plating out there that will last with the heat? Ill look into the car sites as well. Rod.

[DeadheadNM]

Rod found this thread in a search. Not sure it matters but I have a nos example here that is black.

[chewychevy67]

Sweet I have not done anything with these yet. Painted? Plated? What sheen?

[DeadheadNM]

Painted. Has a slight sheen akin to that I'd expect on chassis black. Pic includes the GM parts label and indicates made in USA.

This part is correct for both the LH and RH manifolds on a 72 4wd application but may be correct for RH only on other applications. I have intact CA emissions on my finished 72 Blazer and it has same tubes (pipes GM called them) both sides.

[toms68cst]

Other than some cleaning, I left mine they way they were.

[DeadheadNM]

Also curious if you guys have differing part #s for the exhaust manifolds. My k5 has the heat stove blocking view of the part number. The set I picked up for my new build is composed of two RH manifolds (for 4wd application) that are drilled and believe are OEM. Guess I'm wondering I'd GM used two RH exhaust manifolds for 4wd trucks w CA emissions. Smog tubes are the same.

[RPOZ11]

Well, here is my offering ...
I used to think they were silver cad plated.
But, over time I've learned otherwise.
Some come as painted black, years ago I recall seeing them silver cad.
But today I feel that they were either silver or yellow cad;
Then painted over black.

What seems to me happens,
That after installed on manifolds then ran and going thru the heat process,
the heat transfers across the plating with the paint and it appears to bond.
Over time, this bonding together creates its own brownish hue.

On my tubes, the paint seems thinned out with the bonding processes the heat does to them, and then allows the plating to bleed thru somewhat causing the look of that being a brownish hue.

That's the best I can determine of what the finish ends up looking like

[fleetimus]

Ceramic coat them black or possibly tungsten

[davepl]

Originally Posted by chewychevy67

yeah I am going to de-vein the pump and block the tubes so that it looks the part but is inoperable.

Why? It takes about 1/10th of a horsepower, worst case, and merely injects air into the exhaust manifolds.

Best case it reduces emissions; worst case you never know it's there.

I'm not sure why people are so prone to remove this stuff (though I get the pump is big and ungainly, but in this case you're keeping it anyway). I think it's because it came along at the same time as net ratings, low compression, bad cams and everything else that started in the smog era. But A.I.R. pumps don't hurt performance or economy, so why not just run it in factory config?

[burb71]

I painted mine hi temp black, Im going for a stock resto also

[chewychevy67]

Originally Posted by davepl

Why? It takes about 1/10th of a horsepower, worst case, and merely injects air into the exhaust manifolds.

Best case it reduces emissions; worst case you never know it's there.

I'm not sure why people are so prone to remove this stuff (though I get the pump is big and ungainly, but in this case you're keeping it anyway). I think it's because it came along at the same time as net ratings, low compression, bad cams and everything else that started in the smog era. But A.I.R. pumps don't hurt performance or economy, so why not just run it in factory config?

When I got this motor the correct carb for the smog was gone. I know it has a different part # than the standard 4G carb. Now finding the correct 66-67 only smog carb is nearly Impossable. By 66 most all cars had Quadra jets so I can't use a car carb. 67 trucks were the only vehicles using 4G and smog in 66-67 is rare enough already. I kept the dizzy aside and changed it all to standard. I don't want to mess around with the engine when complete with a system that doesn't work properly because I don't have all the correct pieces. If I had them all I would make it work as it should.

[davepl]

Originally Posted by chewychevy67

When I got this motor the correct carb for the smog was gone. I know it has a different part # than the standard 4G carb. Now finding the correct 66-67 only smog carb is nearly Impossable. By 66 most all cars had Quadra jets so I can't use a car carb. 67 trucks were the only vehicles using 4G and smog in 66-67 is rare enough already. I kept the dizzy aside and changed it all to standard. I don't want to mess around with the engine when complete with a system that doesn't work properly because I don't have all the correct pieces. If I had them all I would make it work as it should.

Makes sense!