Hi Mike,
Happened to run across some dimensions for D3B pins and bushings (Model 27Y-up). These are for straight pins and bushings (sealed type).
Pin # 6B5278 = 28.7mm dia. x 157mm length.
Bushing #6S3178 = 47.1mm dia. x 107.2mm length
I believe the 6S3178 bushing is now a 6Y1717 but need verification.
Thankyou Pete, that is great info to have, I'm going to borrow a NOS set of 2 Ton pin and bush from my buddy Lyoncat and triple check the dimensions, so your info will come in very handy, there will almost certainly be some options out there.
All the best
Mike