Thanks for the comments Ron-well taken. I have no plans to modify the flywheel. Rods will remain unmodified also-thanks for the input. I want to keep the engine as stock as possible and perform a high quality rebuild.
I have removed about 4mm from the piston which puts the top ring 6mm from the top. That's still twice as far as many engines today and I feel it should not be a problem.
I found a NOS set of made in Sweden Deves rings I bought years ago for my 3.5 but they fit the 4.5 also. Maybe I will use them.

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Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT