Over the years I have used probably a dozen or more of the Target Master 350's for cores and have found them to be just fine - certainly no worse than stock cores with equal miles. I've used both two and four bolt TM cores and if they pass muster coming out of the hot tank, they're fine.

By passing muster, I mean the following:

Strip the engine down to the block and have it hot tanked and then inspect for cracks or anomalies. Measure the cylinders and make sure they're within a reasonable clearance to allow a bore.

If all is good - proceed. The other alignment work can be performed at a machine shop to make sure the crank rides in nice straight bearing bases and the decks are square.

The TM should continue to serve you well in it's "second life" as it as in it's first!

Have Fun!
Glenn