First, my thanks to all who post the useful hints and tips that have allowed me to keep a 740 and a 960 running long after they would otherwise died.
Second, an attempt to pay back in part.

My 96 960 had a recurring problem with code P0410, or secondary air. There are many useful posts already on troubelshooting the pump, SAS valve, and controls, but my 960 had a different problem.

I found that the passage within the head going to the exaust was totally clogged. I tried everything I knew to clean it out but without success. There seems to be at least one right angle bend about an inch or two down. I tried solvents, probing, compressed air all with no luck.

Because of the age and number of miles on the car, I was unwilling to do a major teardown and finally, in desperation, made the following modifications which preserve the secondary air function and maintain emission control without a major expense.

First I drilled thru the two center bolt holes that hold the exaust heat shield in place drilling all the way into the exaust manifold and tapped them for 1/8 inch NPT. Into each of these I installed some short pipe nipple with an attached 90 degree elbow.

I made a small metal plate to match the output of the SAS valve, tapped the center hole of the plate and installed a 1/4 inch pipe tee and two more 90 degree elbows. All of the elbows were for pipe on one side ane 3/8 flare on the other. Compression fittings would have been better, but this was what I could find.

The SAS valve was then bolted up to the new plate with a new gasket, and the tee connected down to the new ports with short pieces of copper tubing. I also sealed off the old pipe going into the head with another small plate and gasket.

Two drive cycles, and all the rediness monitors cleared and inspection passed.

I really didn't like doing it this way, but it works. The secondary air gets to the right place at the right time now so emissions are good and the computer is happy. As I live in an area where emissions tessting is required, it was either find a cheap fix, or find another car.

I suspect that the clogged passage within the head is not a rare event with the 960. If everything else checks out, and you are still setting code P0410, make sure that the air passage is open all the way from the SAS output into the exaust.

I hope some of you find this helpful, and thanks again to all those who share information.