A 68 block is not an early block though, it's a late block and should use the big bearing
Also, .001 is not too tight for a stocker, but it does require everything to be very straight
Questions
- Do you have access to a micrometer to measure the journals?
- If you put the bearings in order, to the wear marks have a pattern that might show a bad main alignment?
- Are the small slots for the tabs clean? (I did a Poncho 389 a LONG time ago that wouldn't turn, the tab slots were gunked up, used a small screwdriver to scrape clean)
- Any chance you put caps on backwards or mixed up? Remember "tab to tab" for bearing caps, I say it to this day
- Is it a small bearing crank? The way to check if its the thrust is assemble with no bearing in the thrust and see how it turns
- Did you measure thrust clearance?
My hunch, caps backwards or in wrong place, or small OD crank with big OD thrust is holding the crank up