what engine is most popular

[dogwood]

I would, and am using the Pinto 1800 from the donor.
The CVH is ok as well. Mainly because they are cheap, and parts are still easy to get. You'll find more than enough power in those engines to begin with.

My advice is to use the donor engine for a year, get all the teething troubles out the way. (You will have some, unless you are very lucky, or skilled )
Then do a winter rebuild with the engine that suits your needs.
I thought long and hard about my rebuild, Should I go Zetec etc.
Finaly I decided to fit a 2l injection Pinto. for the reasons above.

HTH David