I needed to determine very precisely the needed compression height of the replacement pistons. First I calculated the 0 deck CH with the 4.5 block and 5.6 crank. It came out to 1.187". I wanted to verify using the actual block, crankshaft and rod so I machined the top of my 4.5 test piston very precisely until I had 0 deck at TDC. Then I removed the piston and measured the pin to top of piston and added 1/2 the pin dia. It was 1.184"-only .003" from the calculated height. I may set it up again and see if I get the same results. Now I add whatever additional for squish (+.010 in my case) which will give me .040" squish with a .050" head gasket. So if I use the calculated CH the pistons might be .003" too tall but it's still conservative for a low speed engine.
EDIT-I just realized I had my rods big end resized and that could have changed the rod length. I have another set of rods I can check with.

Double edit. Same with another rod. Happy my Measurment is close to the calculated figure.

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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