yea I'm still here. My engine project is on hold for now since we are building a house in Nevada. The 5.6 heads will fit an iron block with some machine work but they will decrease the CR on a 4.5 since they have larger combustion chambers. If you have any specific questions I will try to answer 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