Quoting from the book Gurneys Eagles the exciting story of the AAR Racing Cars, in the section on the "mag-ti" (so nicknamed for the used of the then novel materials) section on reducing the weight:
"A big challenge successfully surmounted was the crafting of the exhaust headers in titanium, reducing their weight to 16½ pounds from the 36½ pounds the steel headers scaled."
There are many pictures in the book that show them in painted white. I assume those are the steel ones used at first.
In all through the use of magnesium and titanium they shaved off 88 pounds to bring it down to 1,192 pounds from the original 1,280.
As an aside that was still 92 pounds over the 1100 pound minimum
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss