Id stick with the 1600 you have just rebuilt mate and go efi as above..... if you look at it in black and white you WILL need efi at some point no matter what you do, doing an efi conversion now will make your life easier later.

Nothing too wrong with the zvh mate, but in all honesty it was a bodge done back in the day when aftermarket management and manifolds were expensive, you can probably make a low power zetec turbo for the same money as a zvh.

Good luck what ever you do,

Rob,