from Marine Crankshaft On Jun 15, 2018, Jeff Sienkiewicz in New Milford, CT, USA wrote:
"My new crankshaft arrived today. Side by side comparison. MGB style flange for an oil seal".

This was special order custom configuration from Marine Crankshaft, going into a 1600 race engine. Those with an astute eye may notice the bell shape counterweights on the original crankshaft, making that one original MGA 1500 style. The new custom ordered part fits into the MGA 1500/1600 engine blocks (not 1622 or 1800 engines). It is configured with "ghost mains" in what would be #2 and #4 positions of a 5-main bearing engine, while the three finished main bearing journals are wider to suite the 3-main bearing blocks. The tail end of the new crankshaft is configured like the later MGB 5-main crankshaft, so it will accept a later MGB flywheel and rear rubber seal from the later engines (abandoning the 3-main bearing scroll seal feature).

I hope he never needs a replacement, because it is definitely not an off the shelf part. Put your money where the power is when you go racing.

Here's another similar custom "ghost main" special crankshaft, sitting with a standard crankshaft for comparrison.