So here are a couple more pics that (at least for this particular bolt I checked - and I did NOT check all six of them) clearly indicate there is plenty of clearance between the crank-to-flexplate bolt and the face of the converter. The white sheet is a folder piece of paper stuck between the head of the bolt and the converter body. The 2nd picture shows a much thicker cardboard sheet that still fits quite fine.

Alright, so having said that all I came to discover that as I tightened the remaining motor-to-transmission case bolts, the clearance did actually end up pulling in, which is not something I anticipated, and let me explain what I mean by that.

The initial checks were done with the FOUR top bolts (small block) fully seated. However, as this appeared to be an issue and as I troubleshooted further I noticed that at the very edges where the locating dowels are there was still a bit of clearance, maybe 0.010"??? (I did not measure)

Subsequently once I added the two edge bolts and fully tighteneded ALL of them, it now appeared to almost completely close out the gap I had originally found. Mind you, it was not completely gone, but I would say down to about 0.025" (which I tried to measure with my gap blades, not quite handy getting one in there, but that's the closest I came to getting a good check).

Therefore - and this may be obvious to all of you who have done this countless times - the lesson I learned here is that ALL the engine-to-transmission case bolts must all be installed before anything else can be checked!

Honestly I feel a bit like an idiot to have missed this (I think this was a 'miss'). Thanks everyone for the feedback and troublshooting suggestions though as this allowed me to work through the issue!

Now off I got to fire-up the motor...keeping my fingers crossed we do not get rained out like yesterday!!!