Ok here is the situation. I have a 1994 civic ex vtec sohc. I am swapping in a b16a1 engine this week because the tranny died and its a good time to swap now. So with all this in mind..will the b16a1 work with my sohc vtec ecu and wiring harness or do i have to buy a harness for the b16 and another ecu?

 

It will work fine, all you have to do is make your SOHC harness fit your B16 (extending and shortening a few wires (VTEC, VTM, etc.) just make it fit NICE) You also won't have a problem running on your P28 in it's SOHC form but there would be absolutely no reason to try and get on it like that... It's really easy to chip to DOHC VTEC and it's something you could do yourself with a soldering iron and an 74HC373 IC chip, ROM, and a couple 10K resistors... I would however recommend a chipped P28 over any other ECU (P30/72, etc.) on your car... Good Luck