57' Exhaust Manifold Restoration

[Bob A.]

How should 57' Exhaust Manifolds be restored?

[Jack H.]

Re: 57' Exhaust Manifold Restoration

Simply cleanup (inside and out) with light media blast. If, in your estimation, the exterior is BADLY rusted/pitted, you might consider replacing the casting in the interest of condition points. Check the rear surface for flatness, and, if needed, have a machine shop mill it true to thwart exhaust leaks and use this opportunity to re-stud the base.

Last, but VERY IMPORTANT, visually inspect the fresh air tube that's press fit into the RH mani to bus warm air to the choke. These live in a hostile environment (bathed in raw exhaust gas) and can/do develop cracks & rust-through over the years. A fresh choke tube is a simple $15 item from Paragon (and other catalog houses)....

If yours is boarderline with repect to surface integrity, if could open and conduct red hot exhaust gases to the carb's choke assy. This is a situation where you're LITERALLY playing with fire!!!! More than one beautiful old classic Corvette has gone up in flames in the engine compartment for want of simple due diligence in replacing this component of the exhaust manifold....

[John M.]

Re: 57' Exhaust Manifold Restoration

Bob,
It all just depends what your plans for the car are. If judging is in you plans, then you should clean the manifolds with a light blast as Jack stated and then paint the tops of the manifolds with the engine paint. Most of the paint will burn off in the first hour or so and will leave just enough to make the judges real happy! They really like to see manifolds with paint and rust on them.
If judging is not in your future, then I would blast the manifolds clean and coat with one of the high temperature manifold paints like Eastwoods. This will keep the manifolds looking good for quite a while and will prevent them from rusting. They will however, not judge well with any coating on them.

Regards, John McGraw