I think a ZC swap is in order
That will be cheaper than fixin' the mighty 1.5L - My Dad (the cheapest dude in the world) paid $1200+ to fix his Accord motor after he was too lazy to replace the timing belt and it broke (and bent some valves) at 125,000 miles.
ZC's can be had for about $5-600 and a cheap ECU for $100 - To do it right (replace the timing belt, water pump, plug wires, good ECU etc..) might cost $1000.
To answer your Q - A good strong impact wrench may be needed to break that bolt loose....or a big long pipe on your quality breaker bar. They are a bitch...and since D-series motors spin backwards, as they spin they tighten the bolt, which I think is why they are always so F%#@ing hard to break loose
