Mistral 4 liter weber carburetor intake manifold

Is there a factory Weber carburetor intake manifold for the 4 liter six cylinder engine used in the Mistral and what Weber carburetors were use for 4 liter engine?

 

I've never heard of a 4L having Webers, they would need to be 48s or 50s due to individual cylinder capacity and peak rpm. Anything smaller would be a major compromise and power loss

 

Let me put my question in a different way. If I want to convert my 4 liter Mistral to Weber carburetors, how would it be done?

 

Are the intake ports larger on the 4.0 L heads? If they are not then the standard carb intake manifold should work. The carb size and jetting may take some experimentation.

If you can measure your intake port I will compare it to one of my spare carb intake manifold.

Ivan