More Shankle header woes

["Stefano Iachella" <iachella@domain.elided>]

Hey cats:

Am I the only one who's Shankle headers are falling apart?
They've cracked three times at the exit to the head. First
on cylinder 2, then on cylinder 1, then 2 just cracked again
almost all the way around. 

The exhaust guy who's been fixing it each time says my 
engine rocks more than he's ever seen. He's not familiar
with Alfas though. My Alfa mechanic says it's OK.

I've got a spare used Shankle header that is free of cracks
that I'm going to put on. I'm thinking of asking him to 
fabricate a brace to hold it down by the motor mount
on the engine side. I'm thinking that near the bottom
it must be swinging like a pendulum and stressing the
top of the bend. If the bottom swings with the engine
and not away from it, it should be better, no?

The bottom is not scraping the ground, by the way. He
made all new custom secondaries that hug the bottom
of the engine pretty well. A common response might be
that they bang on the ground too much and cracks will
form. This is not the case, I have plenty of clearance.

Anyone got any ideas?

Thanks everyone for telling me about the exhaust clunking 
at the rear axles. I did see some scrape marks on the
pipe near the sway bar mounts. It looks pretty far away
though, hard to imagine it actually touches.

Thanks.
Stefano.
Oakland, CA

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