Air-cooled Kombi cylinder heads

Is there any difference between the heads on an 1800 and those on a 2.0l engine ? Are they interchangable ? And will the heads from a fuel injected motor go straight on carby one ?
Thanks for your help.

1800 and 2 L heads are interchangeable.

But they do have different valve sizes (2L smaller?) and can have different exhaust port shapes.

Dont think there is a difference with the fuel injection heads