We have a 350 with auto and the problem is that the starter drive gear only engages the flex plate ring gear half way and is chewing up the ring gear teeth. The rig has a new ring gear and starter, both specified for small block Chevy. There is no adjustment to move the whole starter towards the back of the engine, only the spacers moving it in relation to the center line. so we are stuck and need ideas before the new ring gear goes away.
<font face="Comic Sans MS">Go to a real parts store. One that still has a book instead of a computer preferrably and have them look up the various starters that GM used. I believe there were different throw lengths, and there is one that will fit your application, since as you have found, there is no adjustment for length of throw...</font>