broken gf engine

Hi all,

I have a 1.3 golf used in the 30 years of golf publication with the booklet showing the pic of her in the background. Her engine has done 125k and has a blown head gasket.  Im looking for an engine to fit as i dont want to scrap/break her but need to know what fits??!!  I know small block big blok mounts are different so aint looking for anything too fancy.  I would however like to get either a bit better performance or a bit better economy.  I get 37 mpg out of both the golf and the scirocco scala but the scala is a tad faster!

Any ideas how I can make my golf more competitive with its cousin?
i have seen posts claiming a 1.6 polo engine fits the same mounts??!!
Does anyone have a definitive list of engine codes that fit the slot without a bank loan?

Many thanks in advance.

Raymond.