I learned that the 2 inner bolts get torqued higher
than the end ports.
And the end port bolts get the French locks to
keep the bolts from backing out.
This supposedly counter acts the cracking
I guess we will see.....
Hopefully that will work for you. Where I've seen them crack is not up high but down low, closer to the exhaust manifold outlet. Kind of in the area where all the exhaust gas feeds into one spot. To me it sounds like what they're trying to prevent is cracking up higher between the bolts. Maybe they crack there too, but I'm not used to seeing that.
Please keep us updated on how it goes!
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)