The dipstick is where it should be - it has a manufactured twist on the end.

Factory specs are:

60mm for the mains
50mm for the rods

Your crankshaft main journals have been turned down 0.5mm. Your rod journals have also been turned down 0.5mm - which doesn't match the installed bearing size of 0.25mm unless I'm making an incorrect assumption based on the bearing mark.

A loose fit like that would allow the crankshaft to flex and pound the rod bearing...... and the pounding might eventually hammer the crankshaft......... until it broke at the weakest point - which is where they ground off the stress relief fillet radius..... and is the approximate fulcrum of the force exerted by the piston.

Quote
i was about 100mls into my trip when i heard a faint knocking sound followed by a what i thought was a loud back fire or a loud snap


If you want to try rebuilding that block to save money, you might be ok with just a replacement crankshaft..... but I'd be leery of it and would get as far away from it as I could........ then I would quickly turn around and shoot it before it had a chance to jump back into my truck.

Frank

'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum