i recently bought a fully assembled built block, basically everything brand new...but i dont know what kind of water pump it has on it, so i basically need to know if there is a difference between LS, GSR, B16 timing belts??

 

I don't know the exact differences or which ones are different, but...

If the cam gears on one motor have a different amount of teeth than the other motor, they use different timing belts. So, it might be easier to find out how many teeth are on each motor's cam gear.

 

look on the water pump gear and there is a number thats how many teeth is has. Post up at # and someone will tell you what pump you have or go to store and have them pull all 3 off shelf and find the same #. You need to match belt to pump