I have a Chevy 4x4 with a 350. I just out a melling 22110 camshaft in it and am curious where the timing should be set. It didn't seem to run too good at 10 before, factory calls for TDC.  Presently it is at about 8 before,  Thanks  Tony  

Start your timing at zero degrees intial advance and go from there.

What year is your truck?  

1988 0 is pretty doggy. I am looking for overall mpg. So quickest accel, or best idle may not mean much.  Thanks for the help  Tony  

Vacuum Advance?  

I don't ever set timing static,always had best luck just setting total timing.Depending on your cam/operating range I'd shoot for 32-36 degrees and go from there.Jusy my 2 cents  

It has computer controlled vacuum advance.  This is basically an rv cam, not a whole lot of lift, but some increased duration.   Tony  

I always initially set timing by ear. If the timing is advanced too far the engine will be slow to turn over because the spark is predetonating the mix. If it is too retarded you will hear valve clatter when pulling a hill. This range seens to narrow it down to 10 degrees or less. At the midpoint between the two it should be running pretty good. I then make slight adjustments over time checking performance and fuel mileage until it peaks.  

If your engine is computer controlled like my 1987 you should have a wire brown with a black strip near your master cylinder that has to be unplugged. Once this wire is unplugged you can set it the timing to 8 degrees. then plug the wire back in.