I am not concerned about the bolts, more about that alloy block & its threads ability to not be stressed beyond limits in your attempt to tighten the longer bolts which I assume were bottoming out in the holes, reminds me of a guy who rang asking for some 302w ford head bolts one afternoon because he had snapped several while torqueing the heads down , seemed strange to me as I had never encountered the problem..... but this clever fellow was using specs from a 302 cleveland, 110 ft lbs vs the 65/70 the 302w reqd. That was not the end of the story either, shortly after it was discovered that the block had a couple of cracked head stud boss's..... something that Im concerned could cause you problems in the future. Im sure the GM factory shop manual would have torque specs for bell housing bolts, which are essentially what you are/were tightening.