[Dave at Pelican Parts]

How exact a copy of the 2.0 head do you want it to be??

Differences include (but are not necessarily limited to) :
Different valve sizes (and seat sizes)
Different intake port size and/or shape
Different exhaust port size and/or shape
Different spark plug location
Different combustion chamber shape
Different number of intake studs

The valves and seats can be installed relatively easily. Most of the others require welding up some parts of the head and taking material off others.

The 1.8 heads are pretty good in stock form. If you put the 2.0-size valves in, they get a bit better. The rest probably isn't worth it IMHO--if you're going for more than just the valves, have someone knowledgeable flow the ports. Rimco won't do that (that I know of), but FAT Performance in Orange CA will. Rimco will do the seats for FAT, but FAT does the porting.

A big cam (and carbs) will definitely benefit from the bigger valves and porting.

--DD