Stan
  I have disassembled my share of core engines only to toss them in the trash and I paid good money for the privilege to do so 
    I have missed located a dowel pin or 2 in my time and I can say with confidence that the crankshaft does not turn as easily when this happens. The engine in the picture bound from the moment the case was closed and the engine if it started seized in a matter of moments. This was done by a novice with no idea how the engine should feel as it went together.
     case in point I rebuilt a vanagon engine that spun nicely on the engine stand and it seized after 5 seconds spinning with the starter motor. (I felt like burning that van it a that point) After taking it apart I discovered the small nose bearing seized the problem was the dowel pin was to long it measured 8.28 MM that is .011ths to long and it was just lightly pressing on the bearing and touching the crank the pin had points on its ends that stuck out and increased the pins overall length. needless to say I now measure all the dowel pins and trim the points off when needed. The older single port and forty hp engines I later started to notice have dowel pins that are exactly 8mm in length and I use that as my spec for main bearing dowel pins. the day that engine seized was also the day I cut down a bell housing and started spinning engines on the assembly stand to check for oil pressure, leaks and other problems before they are installed.
     
Stan you have overlooked the obvious this was in my opinion an insurance scam to recoup his losses
 this van was torched when he could not make the engine work 

the type 4 case does not snap in place.  the 6 large bolts that hold the case together use plastic locators to center the studs between the two halves.  they prevent the case from closing and only when the bolts are tightened would the binding crank become apparent 

Bob Donalds 
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