i think the E acutally stands for efficiency. i don't really know / care though. the vtec-e only came in the 96-00 civic hx 2dr (maybe some 7th gens too but who cares)
but the hx is actually an interesting bird. this engine intrigued me a little bit a while ago.
first a little break down on vtec-e: at low rpm, one intake valve opens fully. the other one opens just a tiny bit to promote air/fuel swirl in the chamer, and to prevent gas puddling. at the xover point, 2500 i belive, a pin binds both intake valves together, so they both open off the one bigger cam lobe. a little different from the typical sohc vtec found in the y8 and z6. so at low rpms you have good fuel economy for driving around town, and the average midrange and topend.
for more information:
www.howstuffworks.com look up vtec and follow the links.
but the y5 is interesting, because it actually has roller rockers (from the s2000 believe it or not). so, this engine could support a seriously agressive cam, while the followers from the y8 would fail. also, the cam that comes in the y5 stock is actually already more agressive than the y8s vtec cam lobe.
and the way the system is set up, you have quite a few options for a cam... it only has 4 lobes ... hrm...
nobody really cares about the y5 and just thinks it's a stupid economy engine. someday when i'm bored and have some extra cash lying around i'm going to do a crazy NA y5 build. i think this engine actually has a lot of potential that nobody has really bothered to tap yet. it's really hindered by the long tranny and intake manifold. both easily fixed.
but yes, the y7 is pretty damn worthless. the y8 is worth about 400-700 bucks. and the y5 well... i don't know. you need to tell us the code on the block and not just the year and model. it could be a dx/lx (bad) or an ex (good).