Holden HT 1970 Problems

It's all about condition with an old car. The Kingswood isn't a particularly valuable classic car, unless it's in good condition with low miles on the clock. Your uncle's seem to fit that bill. If you go by the trade value it's worth around $2000, but to a Holden enthusiast or someone looking for a cheap classic to enjoy it could worth $6000-$8000. It might be worth showing it to one of the insurance companies that provide cover for classic cars and see what insurance value they would put on it. You'll also find more details on the pricing & specs here.