Would it be possible to build a trike using the engine and transaxle
out of a front wheel drive car. With the radiator and everythign
behine the seat?

I have seen trikes before that did this, but the engine was backwards.
(Radiator was at the rear end of trike.) Why would this be?

I would love to build a trike but most are vw based and those engines
are becomming scarce.