With all these responses, only one person pointed out that your '71 360 is a unique engine. As pointed out, it has higher compression pistons. What has not been mentioned is that it shares the same casting with the 340. 340: 4.040" bore. 360: 4.000" bore. That means you can bore that '71 360 out 0.100" and still have the same meat around the cylinders as a 340 bored 0.060' over. With smaller over-bores, core shift really doesn't matter much. Dude, you got a killer "race" block there!