I had to pull the heat exchangers off to do a transmission swap and was surprised to see in the exhaust ports that three of my exhaust valves are covered in a white powdery substance. Does this indicate an overly lean mixture?
I just had the injectors cleaned and tested and three came back within specs, the 4th failed the flow test. It's in there until I can find another. For the bad injector the exhaust port is more like I would expect, kind of a black color.
I've got the fuel pressure at 31 lbs. Is that too high? It was also popping pretty bad through the exhaust during warm up and high rpm.

Thats a lot of work just to do a tranny swap Mine looked like that to when I swapped my header. I know mine isn't lean since I have a O2 sensor. I think its all the alcohol in the CA gas making the "clean burn"....Just my .02.

.............White valves......popping .....out the exhaust.....during warm up and high rpm,s......TYPICALLY this is due to the VALVE LASH being insufficent., UNBURNED fuel is passing/leaking and being ignited while in the exhaust system.,an additional concern to observe AFTER you set proper valve lash is wheather it STILL pops out the exhaust at high rpms....This can be caused from valves bouncing , off the seats due to insufficient valve spring tension.....AND...The other consern is what is the IGNITION TIMING SET AT.....You may also need to retard the timing slightly, in stages of approximately , 2 degrees, to get it perfect.....Of course Heads , that need a valve job due to old leaking, burned, valves, etc...could also be the problem....ENSURE you have Sufficient valve lash and correct timing before you CAUSE the need for a valve job.......Murray.

I'm going to double check the valve adjustment today and then re-do the timing. Unfortunately, when I pulled the exhaust, two studs stripped out of the heads. Now I get to do that hellish job of drilling and tapping for step studs or helicoils. Also, I found 7, count them...7 copper exhaust gaskets in the ports. Jeesh.

So the white exhaust valves are not the unusual?

I just drilled 2 of mine out, studs broke off. Use step studs or keenserts/timeserts. Helicoils kinda suck and you need the insertion tool and the STI tap for them. The keenserts use a std tap and you can put them in with about anything and set them with a punch.

I never see the std brown/tan color on even my newer car now with the sh*ty gas now. But with the popping, you may be too lean.

...........well scrz914...It,s been my experience that ....stone white, marble bright white, exhaust valves are an indication the engine was/is running too LEAN.... The proper "color" for an ideal combustion burn- for -any engine you expect to have any longetivy...is NOT a bright white...but a shade toward brownish...this excludes a" flakey brownish", or any "flakeness" what so ever....Just a nice firm crispy critter exhaust valve color./coating....on both sides....a proper coating on the valves will protect them, and will act as a heat shield., a similar coating in the exhaust port runner does likewise.....Insulates/reflects the heat away from the aluminum head.....Think of it this way....some people/ racers will ceramic coat the exterior (and sometimes the interior)...of their exhaust system...the objective is to retain the exhaust gas heat in the system..(details/explanation not included here)...a proper exhaust valve and port runner coating does the same thing. ....the long and short of this is... WHITE is a lean burn indication.............................way off topic, but of possably some intrest to some one is ..."back in the day" we tried ceramic coatings on exhaust systems, valve faces,combustion chambers,piston tops and port runners In an endevor to retain every possable B.T.U of heat in the combustion chamber to reflect as H.P. on the dyno...or track , with our 356 scca roadster racecar.................Murray.