Gao - Algeria is possible. A direct BBM (Bordj Badji Mokhtar) to Reggane probably not, the Tanezrouft is closed for tourism. But no problem to travel from BBM to Tam for example.
Security in northern Mali is questionable - take a guide if budget permits or travel low, low profile, especially Tessalit - BBM.
You will need a guide from BBM northwards.
>I am driving a hj 60 and how is it to sell this in Algeria?
no chance to sell in Algeria because of customs - import of old cars to algeria is not allowed.
Price in Algeria would not be good anyway because Algerians need to put the car on an Algérian chassis (a 60/61 chassis is +3000 EUR in DZ) and carte grise to be able to use it in DZ.
Yves (did BBM - Tessalit in April 07)