1968 SB exhaust manifold questions

[Jeff P.]

[Joe L.]

Re: 1968 SB exhaust manifold questions

Hello all, I’ve looked at past threads but usually they are related to BB’s. I do not recall taking off thick washers when tearing down my 68 SB L 79 with AIR. We’re they on all engines ?
Second question, the small tube installed in the manifolds to direct the exhaust into the air tubes , do most of you install these back or do you remove them permanently? Thanks as always.

Jeff------

The washers were used on all small block exhaust manifolds.

If you have functional AIR system, then you need to install the tubes. Of course, if the system is rendered non-functional or removed, the tubes are not required. However, if the air injection "trees" are to be installed, then a spacing washer equivalent in thickness and configuration to the flange on the tubes needs to be installed.

I HIGHLY RECOMMEND AGAINST DISABLING OR REMOVING THE AIR SYSTEM.

[Jeff P.]

Re: 1968 SB exhaust manifold questions

Thank you Joe. I had Bill Hodel restore the complete system so tubes will go back in.

[Joe L.]

Re: 1968 SB exhaust manifold questions

Thank you Joe. I had Bill Hodel restore the complete system so tubes will go back in.

Jeff------


Sometimes, existing tubes will not be reusable. Usually, they are caked with inorganic combustion products and may even be difficult to remove from the manifolds. If you can clean them up and they are not deteriorated or "in-service shortened", you can reuse them. Otherwise, you'll need new tubes. The GM tubes are discontinued but are available in reproduction. These tubes are made from a high nickel steel alloy in order to withstand the heat they must endure.