Well the SOHC VTEC heads from a D16Z6, D16Y8, and D15b VTEC will all work... Ins tock form (the engines with the head and the block) are all roughly 125-128 HP, so they be about 20 more HP give or take... Plus, depending on the head you choose, you may have a higher compression... With either of these heads its best to change to OBD1...

The heads come from these cars:
D16Z6 - 92-95 Civic EX/Si
D16Y8 - 96-00 Civic EX
D15B VTEC - is a JDM engine, so it will be harder to find just the head for... But its essentially the Z6 head with a more agressive cam...