Well wheelbase is conclusive at 39" from front spindle centreline to the point where the seat stays would cross the drop out slots. (at 38" the rear wheel spindle would not be in the drop out slot) Can't measure the frame angles accurately enough as these are coming up at 75 to 77 degrees which is all wrong. With this and the non-cut out BB with under gear cable tunnels I think this makes it an SL which is fine by me, either would do, I was after a later 531 SL frame.