1969 Z28

[JTH74]

I need some advice, I am going to look at a original owner 69 Z with 13K miles. The car has been sitting since the mid to late 70's, so obviously the car will need some TLC to get it going. It is glacier blue with black stripes, flat hood, and the only options it has is rosewood wheel and am/fm radio, no console, and center fuel gauge. The owner worked at a chevy dealership when he ordered it and tried to get factory installed 4 wheel discs because he wanted to road race it, but said he got letters saying it was no longer available, so he ordered all of the JL8 components over the counter and this was installed the day the car hit the lot. His dad had some ties to GM and the 302 was yanked at 2K miles and supposedly a experimental preproduction LT1 was installed. The only non #'s matching item is the trans, the original M20 was swapped for a M22 out of a 70 chevelle. the original 302 comes with the car. If I can get it, what should I give for this car? I know it is not a Yenko,Baldwin Motion,ZL1, etc, but I think its a neat piece, and I don't think I will ever have the chance to buy a 41 year old car from its original owner again. Any input is appreciated, I trust what you guys say from everything I have read here. Thanks in advance.