Someone probably put LS gears on a GSR C/S. Your M/S is fine but you will need the correct gears on the GSR 3 line C/S: 42/38/34/30/26.

So even if I have the correct tooth count on the c/s gears, they may still be ls's and I can't use them?

The LS and GSR both use the same 1st gear. 2nd is the same ratio so you can use either one with the matching synchro. 3/4/5 are different tooth counts for the GSR and LS and are not interchangable.

Ok so correct me if I'm wrong here... On the main I have 13/20/25/29/33, correct for gsr, and it doesn't matter that the ls also has the same 2nd and 4th. And on the counter I can use the 34 off my old counter, my spare 26 and buy a 30 tooth 4th. That would leave me with 42/38/34/30/26, and be correct even though 2nd and 4th are the same number? 4th shows the same tooth counts on this link:

http://www.ff-squad.com/tech/temp/Bgears.htm

Are the pitches different?

The LS and GSR do not have the same 4th. One has 29 on the M/S and the other has 29 on the C/S. 2nd is the same tooth count but a different synchro style.

GSR:
C/S 42/38/34/30/26
M/S 13/20/25/29/33

LS:
C/S 42/38/33/29/25
M/S 13/20/26/30/35

Ok got the right stuff now I believe. Can someone post up a picture of a gsr main 2nd just so I can make sure

You mean GSR counter 2nd?

The LS 2nd will have a gear cone for a one-piece synchro to sit on much like any B-series 1st, 3rd, 4th, and 5th gear. The GSR will not.

I have an ls hydro n my fifth gear c/s is 26 with two lines not 25 what tranny did that come from?

Can we get a list of b16 hydro gears, tooth count n I'd marks for both shafts? I'm swaping the ls 3rd n 4th for b16 and wanna make sure I'm using the correct gears

The 26T C/S 5th that will fit the hydro shaft could be from a 94-01 GSR or a 92-93 LS. The lines can be confusing because there are thick lines and thin lines with various positions on the gear surface. To ID the gear you will need both gear tooth counts with line info and a picture will be helpful.