C3 427 Exhaust Manifolds

[Art Ives]

I have an original set of exhaust manifolds with my 427 vette I’m restoring. When I tried to install the smog tubes with a stainless steel screw beneath the tubes to block the exhaust, the threads in the holes are so deteriorated that some tubes will not make a tight fit. I tried to MIG weld a plug from the inside of the manifold but it won’t seal well. Does anyone have any recommendations? Thanks Art Ives #37880

[Mike M.]

Re: C3 427 Exhaust Manifolds

i had the same thread deterioration of the K-19 exhaust manifolds on my 67 L-71 when i was readying it for Duntov judging. I had the local machine shop use cast iron compatable stick welding rods to seal the 8 holes in the two manifolds. i then used helicoils in the 8 holes to restore threads so I could fasten the two smog pipes to the manifolds. Of course, you have to disable the smog pump itself.The K-19 setup, modified of course, made it thru the judging process without detection Good luck with your manifolds mike mccagh