I posted earlier - Remove items and check first, I trust the user to use a micrometer to measure big end and plastigage to measure the main bearings clearance, the size would be stamped on the underside of the shells and the upper (trapped) ones can be slipped out easily with a popsicle stick. Its not fully recommended but workable if funds are tight. If the crankpins have scratches on them - its useless - remove the crank from the engine.
There are two ways to tackle this with engine out. First by examining everything CAREFULLY and being sure that the pistons, rings and head is good, If the big ends are nice - remove the transmission assy and main pulley/oil pump assy (as required by design) and remove crank from engine leaving the engine intact.
If the upper parts are also suspect (or the conrods are bad too) - tear it down as required and inspect/replace/recondition parts.