[wylde1]

did you notice any change in oil pressure? If your oil pressure didn't change at all it's not likely a bearing. which is good news.

mabye a cracked/loose exhaust manifold or collector? those often happen suddenly without warning and can be very loud and annoying. and if you didn't notice much perfomance difference that could be a culprit. I had some headers on a 400 sbc that no matter how you tightened/sealed them you could always hear some ticking, but usually very quiet and you'd only hear it if you knew what you were looking for.

if the shop thinks it's coming from the bottom of the motor, but your oil pressure didn't change and the oil is clean it could very well be something in your transmission and the vibration is being put to the crank so it sounds like the engine is the problem. might be related to the problem shifting into 2nd, sounds like a bad syncro in the trans anyway.

hope they figure it out for you!