Vicenc,! Great to hear from you again.
And what a great problem to have.
Obvs none of us on here have done a BCW front engine swap yet but it’s entertaining to think about what we could or would do if your car was ours.
My first stop on the innerweb is a search of what engine swaps work in a Chevette. Turns out the 60-degree chevy V6 (the ones for longitudinal duty in trucks and F-Bodies) allegedly go in without a hitch.
Chevette guys are all over this particular swap. Imho it makes a lot more sense than trying to shoehorn a V8 in there.
A Miata swap would also be awesome, imho. I’d try to get the whole drivetrain to work. It would have to fit, though I’d imagine you’d have to make the frame mounts for the engine.
Hell, I’d bet just about any this-century dohc four cylinder car engine could be made to fit, and wired to run, in a BCW TD body.
Maybe a 2.5 Ecotec?