Z28 exhaust manifold crack opinion

[Hotrodpaul]

I would be curious to know how this comes out as I have a cracked manifold on my original 69 Z-28 that I plan to repair. My guess is that some preheating and slow cooling will be required to prevent a brittle high stress weld area and to keep the weld from cracking in the future. Remember the manifolds are subjected to large thermal stress cycles of expansion and contraction in normal driving, probably what cracks most manifolds in the first place.

Paul