1994 vs 2000 1.8 motors need opinion
 

Putting together all of the parts to to turbo one of my miata's.
My 1994 is in overall much better condition than my 1992 with the 2000 1.8 swap. 1992 has suspension upgrades, rollbar, etc. The 1994 is stock.
I really would like to use the 1994 to build, but I need to know if there are major differences in the motors. (2000 vs 1994).I would swap the upgrades from the 1992 to the 1994. Not sure what makes the most sense.

The bottom ends are similar. Slightly higher CR on the '00 motor, no holes on the side for water/oil to feed the turbo. Nothing earth-shattering.

The head on the '00 motor is significantly better. Straighter ports, more lift / duration on the cam, solid lifters, yadda yadda yadda.

Build up the '94 block, and then swap the '00 head onto it when you're done?

Joe, sounds like a plan. I would assume I could put the 94 head on the 2000 motor so the car can be sold to help fund the build on the 94.

Yeah, the '94 head will fit on the '00 bottom end. It won't have the correct hole for an NB cam sensor, but so long as it's going into an NA, it'll be fine.

The intake manifolds need to stay with their original head- the ports don't align. Pretty sure the exhaust side is interchangeable, with the exception of the EGR ports being different.

Are all the 1.8 crankshafts interchangeable?

According to the parts catalog, the '94-'00 cars used crankshaft P/N BP06-11-300C, and the '01 and later cars used BP06-11-300D. Subtle differences in P/N like this often represent subtle changes that are still form-fit-function compatible, such as a process improvement, supplier change, etc.

We know that the FM stroker crank is compatible with all 1.8 engines, and that the main and rod bearings are the same, however the thrust bearings are different for '01+. Whether the new thrust bearing is a result of a change to the case or a change to the crank I cannot say, though it's likely that some combination of bearing-to-case or bearing-to-crank matching will permit complete interchange.

What's your thinking here?