Bought a 200 block but the hole is bigger on the new block compared to my old one ?

 

Not unusual if its had any sort of competition history , the hole youre on about is drilled to accept a Dash 10 Aeroquip union and acts a return to the gallery when using a remote filter .
May be something totally different of course but any engine ive ever used /built has this done .

 

No you're spot on m8,harvey sorted it for me on the phone.