Motor Mount Help

Just went down this road! Took a 318 out of a 75 Dodge shorty van and worked it over. Tried the mounts with the engine- not even close! A friend told me 273 mounts would work just fine, so I borrowed my 273 mounts from my other 66 Barracuda. Still no go! Had to weld an extra triangle of metal to the passenger side mount and drill it to get it to work! Hope this helps!