With your car having a small block Chevrolet motor in it some things have already been changed to make it work.
Motor mounts and frame brackets are different but you can buy new ones.
The fuel lines are on opposite sides of the motor.
The starter is on opposite sides.
The exhaust manifolds or headers will not interchange.
Transmission bolt pattern is different.
More than likely the battery cable and wiring to the starter has been altered.
Like mentioned above the wiring harness from the firewall more than likely has been altered.
It's not a bad idea to install new wiring in the engine compartment. The old wires get brittle fro old age and the high heat.
I'm sure I'm missing something. LOL

With all of that being said.
I started out as a Chevrolet/Camaro guy. I bought a Firebird and my direction changed. LOL
If your going to keep the car and your not worried about resale put what ever motor in the car that makes you happy.
Small blocks are less expensive to build and can be found very easily. Aftermarket parts are much lower in price.
Your car is already set up for a sbc so it will be less work and money to go that same direction.

Like mentioned above the wrong motor in the car turns some people off. I prefer to see a Pontiac motor over a sbc or a new LS transplant. I have even caught myself going to look at a Firebird at a car show and when I see the sbc I walk away.
But, I think that is pretty shallow. A nice car is a nice car.