Part Number / Help

[Andrew K. Mattei]

Hopefully someone here can help me help someone else out...

A guy emailed me, and we've been exchanging mail over the last few
days... - he's having trouble with his VATS module, and I presented two
options to him - the 555 approach, or the reprogram the EPROM approach.
Turns out he has no EPROM to reprogram (he just bought the car, non
running, and the MEMCAL was not in there, but the computer was... go
figure). 

My theory is that a reprogrammed MEMCAL is better - no additional
hardware to break, or wire in.

He priced a new EPROM (MEMCAL?) at his dealer for $85, part number
16161123. He's got a 1991 Camaro RS, 5.0L TBI, 5-speed, with A/C, ECM
part number 1228746. However, we don't know if this MEMCAL is without
VATS. Does GM produce a VATS-free MEMCAL for this car/ECM (and if so,
anyone have a part number ;^D)? If not, would anyone be willing to help
me with the hex address of the VATS enable bit? (I've been through the
archives on this, and came up dry... would just need to disable the
checksum and disable the VATS)...

Any ideas would be very greatly appreciated, both by myself (learning
experience!) and the guy I'm trying to help!

-Andrew