HI all... I am new to all this

Hi all... I'm currently invovled myself hip deep in a pile of poo...lol I decided to put an 350 tbi motor into a 84 K5 Blazer... I know this will do this vehicle justice... My donor was a 88 V1500 GMC Suburban 4X4... I have already swapped over the motor with the tbi and the rebuilt 700R4 trans with NP208 transfer case... I unhooked the wiring from the fire wall and fished the harness through the fire wall to the ecm... pulled the ecm from under the dash... never unhooked any of the wiring from the motor as I know nothing of efi at all... I've switched out the ecm's and hooked those connections back up... but I noticed the wiring for the fuse blocks is way different as where the pins are... anyone have any idea on how to be able to use the factory fuse block in the K5 to power this harness or do I have to use an aftermarket fuse block to make this work???