Yardpro

i am doing a cayman ls3 swap. part of the kit i bought separates the two heads water ports and uses an electric pump. it has hoses from the pump, one for each head, exhaust is the same. The pump is on the drivers side of the motor, so not much of a run to the heads. i am having problems fitting the two 1" lines i thought i needed. Can i use 2 3/4"?