Oh yes but I have no idea which ones other than CA which has a law for everything.
If you use the basic block and bolt all the old stuff on to include the emissions stuff how are they going to know other than chasing down a casting number.
The jaw keeps folks from getting around the emissions equipment for the model year if the vehicle.
With that said if all is still installed at the finish what's the problem. None that I can see.
So you use the stepped long block and bolt all the 1990 stuff back on. Nothing to mess with in wiring or ecu and should be legal and pass any inspection.
The block doesn't know any different it only does what it's told.
The biggest problem is mount homes with the different casting series.
Sent from underneath my Jeep
89YJ 2.5L TBI, AX-5, NP231 SYE, Ford 8.8, Yukon Grizzly, Tom Woods Shaft, 33" BFG T/As, 4" lift, Warn VR10000s.
AF Jeep Club Tail #184