Hey ThirdGen. I'd like to start a thread and have you all ad what you know about this topic. There are so many different tachometers. I believe I have a grip on most of them but I have a few questions that remain. After I pose this first question I will list what I know (or think I know). So heres my question.

I have an 87 IROC TPI with T5. The tach is the 5k yellow and 5.5k red. The oil gage is attached to the back of the tach but can be removed from the tach. I have other tachs, some with the same yellow/red and some with different yellow/red and the oil gage can not be separated from the tach. My question is... do any of you know for sure (no guessing please) what cars got which one of these tachs? Most interested in knowing what cars and what years got the detachable oil gage.

And now for a partial list of what I know so far about the tachs

82 and maybe 83 I think had the speedo/tach combo?

I know very little about the tachs from 83 and 84.

1985 IROC came with 4.5 yellow and 5k red with engine options LG4/L69
1985 IROC with LB9 got the 5k yellow 5.5k red regardless of transmission
1985 everything else.... I have no idea and never cared. Anybody want to ad here?

1986 IROC all got the exact same 4.5k yellow and 5k red
1986 everything else.. once again input here is needed

1987 IROC 5.0 LG4 and 5.0 TPI with auto trans got the 4.5k yellow 5k red
1987 IROC 5.0 TPI with T5 got the 5k yellow 5.5k red
1987 IROC 5.7 got the 5k yellow 5.5k red
1987 everything else... Help here?

1988 IROC all the same as 1987 see above

1989 4.5k yellow 5k red used on all 5.0 TBI engines regardless of trans and on the 5.0 TPI with auto trans
1989 5k yellow 5.5k red was used on TPI 5.0 with T5 trans and all 5.7

1990 4.5k yellow 5k red on all 5.0 without G92
1990 5k yellow 5.5k red on all 5.0 WITH G92 and all 5.7

I got nothing for 91-92. Need input here to fill in the blanks