rod bearing
I hate to be the bearer of bad news but the only way to change You're rod bearings and have as close to 100% certainty as You can that it will last longer than the break in period is to remove the engine from the vehicle and if You;re fairly mechanically inclined and confident, then get a book on rebuilding the LS gen 3 & 4 chevy small blocks and do it right because if You try and install new bearings with engine in the car not only will You be frustrated at how hard it will be but very little chance it will work longer than it takes to barely break in the engine. Or probably You're best bet would be to get a junk yard truck engine like a 5.3L or a 6.0L ,,,,,,,etc
