rx7drift90

Hey guys, me and my friend have been working on a 1990 13bt rx-7 for the last few months. just before winter we realized the car had problems. we thought it was the maf the fuel pump so we replaced everything and then finally realized the engine was blown. so we pulled the engine out and are going to get a 13bt and re install it. there is just one problem. when taking the engine out we cut the wiring harness going from the motor to firewall on the right hand side of the engine(looking at engine from front of car) now the only thing is that we realized we have to take a lot of stuff off the block to get the wiring harness out. so when we get the new motor we have to either take everything off and feed the wiring through and then splice it or cut the new harness and just try and wire it up properly. theres like 50 wires and if anyone could help me out with my problem i would greatly appreciate it. sorry for the story. i just dont know what to do with it. thanks for any help in advance.