I'd start by verifying the year of the chassis and the body. This can be done by finding the VIN numbers. On the frame, it's stamped in two places.
http://www.fordification.com/tech/vin_find.htm
The last six digits of the VIN are the consecutive unit numbers, and you can compare them with the numbers on the VIN decoding pages (links are at the bottom of the page linked to above) to determine the year.
As for the engine....more than likely you've got either a 360 or a 390. The 360 and 390 blocks are identical externally. The only way of differentiating between the two, since there are no external markings to tell you what you've got, is to measure the stroke. Simply rotate the crankshaft around until the #1 cylinder is at TDC (top dead center) as indicated at the timing mark. Remove the spark plug and insert a wooden dowel into the cylinder until you hit the top of the piston and make a mark on the dowel. (Use the valve cover lip as a constant reference source.) Then remove the spark plug from the #4 cylinder (when #1 is TDC, #4 is BDC) and make another mark on the dowel. Then measure the difference. A 360 has a 3.50" stroke and a 390 has a 3.78" stroke.
67-72 ford trucks have always been my favorite since i was a little kid, and now i have one. Only the greatest trucks ever made would have there own website and a dedicated following such as ourselves. I bought a truck from a guy and he told me that it is a 71 chassis with a 72 body. he said it has a 390 in it, but before i start buying parts for it i would really like to confirm that it is truly a 390 and also what year it is. any suggestions???? 
from Texas! 
