400/450 stroker....Cheap parts, lotta work.

if you didn't do any of that, and kept the rpm maxed at 5500 rpm, it wouldn't matter too much would it? It would affect longevity, and smooth operation, but the bearings wouldn't suffer immediately would they?
I don't think it would cause any problems at all.

Just spitballin.....why not play around with the big end center line and get the lengths equal? index the crank first of course and then even the lengths of the rods with the big end placement. Bad idea?
If I had the equipment to do so I would have tried to make them all the same length. However I'm dependent on others to rebuild the rods.

What is your goal for power production ? What kind of torque curve ?
I have no idea what this engine will do. I've never built one like this. We'll test it with the stock cast iron intake and HP exhaust manifolds, shop headers and two or three different aluminum intake manifolds.