Injector timing

[gmnut55]

On my 6-71 turbo engine I have a bad injector.  I'm replacing all six, they are the 7a77 and the plate says to time them at 1.490. The ones in there are timed at 1.500. Should I time them at the 1.500 or the 1.490? Thanks

[luvrbus]

!.500 is good setting you are just changing (advancing) the start of the injection stroke not the amount of fuel,they burn cleaner at 1.500 with less turbo lag ,1.490 is good too just a little more smoke  ? what calibration are the new injectors low,med or high,The 7a77 injectors only place I ever saw those were in fire truck engines back 87 and 88  they did have a 1.506 and 1.496 setting too   

[gmnut55]

They are medium calibration.  I will set them at 1.500. The motor came out of a truck and completely rebuilt and turned left hand. Thanks for the info. Mark