IMO-
Decent looking 69 big block-- looks like 427/390 4sp . . certainly not very clean with incorrect seat covers and at least one heavy repaint. Frame doesn't look bad at all- but is that SHAG carpet under the fuel tank?? And looks like incorrect seat material-- cloth inserts instead of leather or basket weave. Depending upon mileage, matching numbers info and examination of seams for damage history I'd give a FWAG at $18-$25k ?
A bit more info would be helpful although I'm sure I've gone out on a limb far enough to fall off ! If you say that the seller's asking $10k, I'd buy it - - or $50k and I wouldn't be surprised!
Regards-
CQRT in AZ