it does lower the displacement compared to an ls. the reason gsr internals were used is because i just put together my gsr block. there was an issue with the number 3 wrist pin that failed and slid out the piston bore and dug 2 grooves in the cylinder wall due to not being pressed on properly when the pr3's were installed. i needed a spare block and a ls is what i was able to source. i picked up the ls completely bare from custom240 here in TR. everything was swapped over from the gsr. so 00 gsr oil/water pump, headbolt and the timing belt was replaced back in april when it was a stock motor. lsvtec kit was purchased from blackshadow here on TR also. i believe the kit was pieced together but everything is teflon taped.