[AT] carburetors On topic (kind of)

[ROBBRUT at aol.com]

Andy-
My experience with big Caddy motors has had exhaust as the issues, for two  
reasons:
The first was that slipping one into a smaller space dictated some  
semi-restrictive bends, etc, which a smaller cube engine would have tolerated  and it 
lost lots of power, which we recovered soon after by spending time to  re-route 
the pipes.
The second instance was a stock Caddy which ran fine at part throttle, but  
lost major power when full throttle was applied.
We eliminated all of the usual suspects one at a time, and were on the  verge 
of setting it afire to get the insurance money, when a former Caddy  mechanic 
came by.
He said "it's the exhaust pipe".
We hooted at that because the pipe looked like it was factory-fresh.
Turns out that Caddy made what they called a "triple wall" pipe to cut down  
on passenger compartment noise, but the inner layer/tube would sometimes 
corrode  enough to break loose and collapse under higher exhaust flow rates, almost 
fully  blocking the pipe. as soon as the pressure was relieved, it would move 
back into  place and everything would seem fine.
We had a new headpipe bent up out of single-wall tubing and everyone was  
happy again, even at full throttle !
-Bruce Thompson