Would the 4.7 liter from my 1999 Jeep Grand Cherokee fit in an A body?

I am sure it was good for that. The actual design is proven. It's the same basic thing as the little Benz V8s. Reliable. But in a Jeep or similar, mileage sucks balls.

The biggest thing I have seen about them is the oil pickups getting too hot and cooking the oil in them and stopping them up. Jasper sells their 4.7 reman with an oversized pickup to help solve it.