Bore wash tends to kill rings before anything else, as they run effectively dry.
Little ends and tappets sound totally different, if it was tappets they wouldn't all do it, if they did and it was down to oil pressure you'd have a lot more to worry about, does the oil light go off right away ?, disconnect the coil and spin on the starter does the oil light still go off almost immediately ?, if it does stop thinking oil pressure.
The tappets which get affected first tend to be the rear exhaust side ones on no4, these are the last to get the oil supply also, and where the crap collects from the congealed oil, there are blanking plugs on the ends of the oil galleries either side of the head, when rebuilding these should be removed and the oil gallery cleaned out each side.
If it sounds as though it is coming from the rear of the engine, is it worse when slowing down from high rpm through the gears ?, if as I suspect it is, then think clutch arm rattle, the rubber boot can become dislodged where it passes through the bell housing, so it rattles on the alloy window, another option is clutch plate rattle, the springs in the friction plate can break, esp if doing many hard wheelspins, these cause a monumental rattle, but apart from being annoying do no damage.
tabetha