Be careful, Like Tom said they are the same as SBC but some from the auto parts store are not the same. The thread length & the knurled area may not be the right length. I have a ruined 350 in my '99 Yukon because the knurled area was drawn too far into the hole and cracked the block. A piece actually fell out and the starter can not be tightened. Good 4x4 if I could start it.
I have seen some marked for Small blocks that are different lengths and some with no expanded knurled area at all.
