It is all about condition. You can check out this site to give you an idea.
http://www.nadaguides.com/Classic-Cars/1968/Volkswagen/Transporter/Pickup/Values
In order to know what the value of a 1968 Chevy pickup is worth, you will need to know more details about the truck. You will need to know the condition and miles of the vehicle.
If, by ECU you mean "Engine Control Unit", I don't believe a 1968 dodge pickup had one.
$980,000.00 in 1968 had the same buying power as $6,837,595.87 in 2016.
$1,000,000 in 2016 equals $143,325.23 in 1968.
1968
Try nada.com
ALOT
8 cylinder 360
127" (same as a long bed pickup)
Not without major fabrication.
4.5 million dollars in 1962 was worth about $35.3 million in 2015.
Yes it can, you will also need the big block pickup tube