Head Castings

All of you "in the know" Subaruists here is a question. Did Subaru change the head casting when they went from the early EA81 engine with solid lifters and the 1.563 intake valve to the later EA81 hydralic lifter engine with he 1.654 intake valve or did they just cut for, and install larger valve seats to accomodate the larger intake valve?

If my hunch is correct they did no major retooling but simply installed larter intake valves. If this is the case then all one would have to do is have a machine shop put larger intake seats and valves. I have been told by competent authority that we should never "screw with the short radius" in the intake port. That being said the only thing that can be done is install the vlaves and "run what ya' brung". Any thoughts or experiences.

I also found a web site that listed every "Hitachi Carb" that was ever installed on Datsuns from 1973-1987. It gives there model numbers. If I understood the other post that I have read about how to deterine the primary and secondary barrels based on the model number of a Hitachi carb one should be able to find an Hitachi that will fit the late model EA82 Carb intake manifold so that the car will still look stock when someone lifts the hood and spots the "stock air cleaner". I saw a model number DCH360 which translates to a 30 Primary and a 36 Secondary. It has a one wire electirc choke. Food for thought??

YEPABUS