Would agree its not the greatest engine, but deffo a good upgrade from a HCS rattler. A good cvh with healthy carb and 4 branch is still nippy when the car is so light!
You can use your alternator and starter on the cvh no problem, radiator will need to be changed to an XR3i item (i''m assuming its a mk4 Escort your talking about) and you will need a cvh rear engine mount as HCS mount is totally different.
Apart from that you sound pretty much covered. Might as well upgrade to a 5 speed box when your at it!