are these the same exact engines, I mean can I use one out of a accord for my prelude using the same computer and harness

 

the f22a1, f22a4 or f22a6 are all going to bolt in, and as you said you would use you computer and harness.

 

F22A1/4 are exactly the same no matter what car. Only difference is the Prelude ECU has a slightly more aggressive map vs the Accord ECU which is set for better milage. The F22A6 is the same block wise, but uses a dual stage intake manifold (like the H23 and H22), and has an ever so slightly more aggressive cam (5hp difference). Either way, any of those 3 engines will drop right in a bolt up, but the A6 would require a different ECU to activate the secondary intake runners