Value for 2 properties in Blacktown

Hi, hoping someone can give me some advice on the below please.

I have a property in Blacktown, around 680m2, dual street frontages.
The property next door is up for sale, I cannot afford to buy it but I am thinking that I may sell mine. Does having the 2 properties for sale significantly increase the value/sale price. Combined they would be around 1360m2, both with 2 street frontages.

Thanks for any help you can offer.
Cheers

Value for 2 properties in Blacktown