Why don't we all stop messing around here and accept that a short block Chevy Vee 8 would be ideal ( subject of course, to impoverished GM undertaking the type approval)
There is also the point that, in relation to a 4/4 substitute, there really are much more suitable engines around which would not only 'package' better but give a far higher quality baseline unit than the Ford. I've been around Ford engines all my life and would never decry their advantages but quality- they aint.
At the risk of being a heretic, why do we think Lotus went from the fairly dreadful K series to the Toyota lump. The days when small volume British sports cars can expect their owners effectively to pay for turning Low tech into Hi-tech via significant amounts of post purchase expenditure must be numbered

Regards,
G ( Being a recidivist!)