"L" shaped cranks were supposed to alter the point of application of force to maximise it at the straight ahead position. The idea being you couldn't apply maximum force when on the return stroke.
Never quite understood the principal myself as the pedals still travel in a circle with the radius at the centre of the BB/ cranks......
Now eliptical chainrings..........they were different and had some sort of *real* physics applied to them LOL
The bit that mattered was Ian Cammish used them and he won loads of TTs...and many associated his victories with the L shaped cranks...when he would won on cranks made from blasa wood as he was so good as a TT cyclist......he failed when he went to mainland Europe and came back to his British TT domain....i believe the expression to describe the cranks ability to improve cycling performance is called 'snake oil'!
I have Mr. Cammish's actual PMP cranks with me with the L/H one cracked. I just love these PMP's & have 2 sets myself
The bike could do with a 57 Campag Ring IMO