89 crank in 88 block

Do I just need the front crank seal retainer? The crank seals are different and will it work?

[iTurbo]

No workee! '88 is pre-commonblock. '89 is commonblock. The crankshafts do not interchange.

[86Shelby]

So what all is different? So the snouts are different sizes. then change/modify one to fit. What about rear main seal diameter? Main bearing width? Thrust bearing different? If that info gets out there's a chance that someone will figure out how to interchange them, or at least use late cranks in early blocks or vice versa, etc.