The Omega gearbox is somewhat taller than the standard MGB box. I was concerned that it wouldn’t fit so I performed a similar mod to what you’d do if you were fitting an LT88 or R380. I’m not 100% convinced this was necessary. I chose to do the mod slightly differently to how Rover did theirs. My method was less crude. I effectively reshaped the horizontal seam where the transmission tunnel meets the bulkhead & reattached it in exactly the same way but as a curved joint rather than a straight joint. I gained about 10-15mm of clearance & it still looks factory.