OK then, let me search again.
Using I believe the 1990-91 LT5 ECM is PN 1228331,
These guys repair them for $449.
http://www.autoecmcomputerexchange.c...oducts/1228331
White Racing has one for $699
http://www.ebay.com/itm/Corvette-ZR-...item4af1421c5c
This one is $895, but with a $300 core return.
https://www.autoecmstore.com/collect...oducts/1228331
I also believe that the LT5 ECM PN 16196394 works for 1990-95 with the correct Prom for that year installed. According to Mark Hailbeck. "The details of the testing are described below.
GM used three ECM part numbers across the six model years.
01228331 1990 to 1991.
16163993 1992 to about 1993 1/2.
16196394 about 1993 1/2 to 1995.
AC/Delco supplied the 16163993 as a remanufactured unit for repairs from about 2004 until about 2009. They shipped 16163993 regardless of what model year was ordered.
I removed a factory installed 1990 01228331 from a 1990 car. Then installed a 1995 BMCB calibration chip and installed the ECM on a 1995 car. Everything worked normally. The engine went into closed loop fuel control, it went into learning mode, the EGR worked normally, the ASR worked, the momentary contact full power key worked, and the engine data scanner displayed engine rpm with a resolution of 1 rpm. The ALDL data stream ran at 6.6 frames per second, just like a 1995 ECM.
I removed a factory installed 1995 16196394 ECM from a 1995 car. Then installed a 1990 AYBK calibration chip and installed the ECM on a 1990 car. Everything worked normally. The engine went into closed loop fuel control, it went into learning mode, the full power key worked. The engine data scanner displayed engine rpm with a resolution of 25 rpm. This is normal for a 1990 car. The ALDL data stream ran at 6.6 frames per second, just like a 1990 ECM.
A 16163993 ECM was tested in a 1995 car and it worked normally as a 1995 ECM would."
Based on a search for PN 16196394
http://www.gmpartsgiant.com/parts/gm...-16196394.html $220
http://www.autoecmcomputerexchange.c...ducts/16196394 $320
White Racing has one for $$649
http://www.whiteracingproducts.com/i...oducts_id=1475
Always contact the vendor by phone and confirm their return policy. Beware of the low price bargains...