engine swap question

Ok sorry to ask a stupid question but I've done all kinds of searches, both with Google and on here and have been unable to find an answer so here it goes.

I have a '98 Civic HX that I recently bought and while trying to find the correct IAC valve for it I discovered that someone in the past had done an engine swap on it. I should have a D16Y5 and I have a D16Y7. While trying to find parts this has caused many problems since I don't even know if the engine is the same year as the car. Is there a way to tell the year of the engine from the serial number?

Also how do I know if the engine swap was done correctly without paying the Honda dealer hundreds of dollars to look into it? I was told by the Honda dealer that this could cause further problems if it was done incorrectly or the proper parts weren't replaced.

Any help would be appreciated. Thanks.

Well when buying parts motor related it will be for the d16y7 not the d16y5. The year of the block is imprinted on the from of it, here's a pic: http://img.photobucket.com/albums/v473/CivicSpoon/blockdate.jpg
As far as making sure the engine swap was done properly, just look around the engine bay. Look for beat up wires, extra wires laying around, busted or ripped boots on axles, oil leaks, listen for knocks in the engine, clicks grinds or whines from the tranny, throwing ECU codes, missing or stripped bolts and screws, ripped mount inserts, too much play in the shiftlinkage. The D16y7 is a '96-'00 sohc non-vtec engine from a CX, DX, LX (I'm assuming the VP also) and has 106hp (where the correct engine for your car has 115hp).

Thanks for the info, I'll look for the year there. I only bought this car a month ago and it's really turning into a nightmare. Never would've crossed my mind to check that the car had the original engine... oh well live and learn I guess.

Thanks again. :)