My previous Tenant has left behind an engine block and all I know is it's a V8 with a oil filter called "BALDWIN B6". I'm just wondering what size and type of engine it may be.

No way of telling from here. You can post pics if you'd like. I can identify most. May be worth something.

V8 ENGINE BLOCK- FREE!!! - Edmonton Car Parts For Sale - Kijiji Edmonton (http://edmonton.kijiji.ca/c-cars-vehicles-parts-accessories-V8-ENGINE-BLOCK-FREE-W0QQAdIdZ87600877)

Click on the above link to see the pictures

350 Chevy V8. You'll most likely get someone wanting it for scrap value. But, at least it will be gone, eh?