'64 Dart V8 Exhaust Manifold and Oil Filter Options

I found a 273 equipped '66 Barracuda in a local yard and have already stripped the K-member and throttle linkages, etc from it to do a V8 conversion down the road.

Should I pick up the 273 Exhaust manifolds too? Will the manifolds fit on a 318? What are some other options for better breathing exhaust on an early A with a V8?

Also, will the oil filter adapter from the 273 fit onto any other small block engine? Will I need that for a swap? There was an 80's Fifth Avenue right near the Barracuda and it has a different oil filter adapter.

I will go back today and get those things if needed, before the car is taken away and scrapped!