I agree with GMC , use all the corvette stuff.
The vats will be easy to bypass. Just place a resistor the same value as the pellet on the key, hardwire it to the 2 wire orange harness under the column harness and you are done. Be sure to keep ALL the corvette harness as the VATS module may be a seperate module as some /most were.
Having the whole vette...you have evrything you need to do the job.
Buying an aftermarket harness /ecm etc is a waste of money.
Wished I lived closer, I would swing by and give you some very helpful pointers. The wiring /conversion you are doing is a blast, and easy.(at least for me it is
I'll watch this post and help you out here . Way cool .