I'm in the middle of rebuilding the 7.4/330, have all torn down and was flushing the water passages. The amount of "crap" that came out of it was amazing. It looked like a pound for rusted metal flakes came out on pressure washing it. Is this normal? It looks pretty clean in the passages now. The engine is an '88 and by the looks of it hasn't been apart. Granted for a 16 year old engine that has seen some salt time, it is good shape internally. Should I have the walls sonic tested when it goes to the shop? Is it worth the extra $$ for it? Or should I just go with it. It's only going to be build up mildly.

Thanks-
Chris

Good question.I can't resist but you live in vegas and I would gamble on it.

In my opinion, sonic testing is not all that accurate. The cylinder walls and remainder of the block will be checked in a few spots, but it wont be tested everywhere. If the block looks old and worn, put your sonic test money towards a new block.