I have a 1987 4/4 4 seater with a Ford CVH motor. Last December I ditched the old 1600 CVH and installed one of the American long-block CVH motors bored out to 1900cc. This is a completely refurbished engine, balanced and ported, supplied by :http://www.specialisedengines.co.uk/index.html.
The motor is identical in appearance to the old engine as I did not want to change the appearance of my car in any way.
I am extremely happy with the results. A much smoother engine with more power and torque. No more paddling in 5th gear at lower speads. Good passing acceleration as well and easy cruising at 70 mph.
I would certainly reccommend Specialised Engines to anybody considering an upgrade of a 1600 Ford CVH.
Cheers