Anyone knows whats the differences between those 2 trannys? I am planning to put on my LS. I heand this is a very good mod to a LS. Is that true? Also how can you tell thats a close ratio tranny than a regular LS tranny by just looking at it. I have a guy offers me a JDM SiR cable tranny for US$150. Thx.

 

The JDM SiR tranny is probably a Y1.It has taller gears and F.D. than the 92 USDM GSR(YS1)tranny and is not as strong-synchros go quickly(if they're not already gone)and they have a smaller input shaft.Unless you know what car the YS1 came from,it's easy to get burned-I know!You can't really tell if it's a GSR or LS tranny visually.

 

So does it bolts on to my LS? Do I need to change the clutch disc cause of the shaft?

 

If it IS a Y1 it will bolt up to your 91 LS using your stock clutch disc.

 

thx man