I find it funny that I went through the same thing. The first time I used something other than Three-bond only because the price was high and I already had the other stuff. Not to mention I was lazy and didn't want to go get it. It ended up costing me way more time.
As a side note, I changed my water pump seal while I was in there. My '02 had two seals and my '97 only had one. The '02 also had an alignment pin in the water pump housing that the '97 didn't.
ps - the '97 620 is the one that now has an '03 hi-flow head and cam on it.