to get 2 ltrs from A-series engine you are talking 91mm bore [for A14 crank] and 88mm bore [for A15 crank] This guy has made no mention of stroke what so ever. With those huge bores I would think that the steel between the cylinders would be paper thin.
I find it very hard to believe.

1608cc is about the limit.even then I would use it on the track only. I guess it is possible to squeeze in an E16 crank, but you would have pretty serious angles going on with con rods.