460 starter/flexplate issues

I am having issues with my 460 in the ranchero here. The old 400 starter I had in there worked a couple times but after the initial break in it made an awful grinding sound, when I took it out today it had rounded a couple teeth off the flex plate, so of course I have a bad spot on the plate now. I also replaced the old starter with a new reman one of the same style (also for a 400) got it to start once and found the bad spot again. I am wondering if I have a different year flex plate or something? So until I get some new or different ideas I am somewhat at a standstill. I am also considering switching to the 460 starter that has the integrated solenoid and wondering what kind of mods I may need to do in order to use that one.

Edit: the harmonic balancer I have here has a D9 casting number on it, does this make a difference with the big blocks like it does with the small blocks?

When I swithched over to the new style starter, I just put the starter cable with the battery cable on the same post on the solenoid on the fire wall, and then put a #10 copper wire on the post where the starter cable was, and ran that down to the solenoid connection on the starter. Kind of redundant, but works well to keep all the power going where it needs to go without having to rewire a whole chassis.

DID YOU RESOLVE YOUR STARTER ISSUE???
I have a D9TE=ab 460 in a 1979 ford f-250 I purchases
the starter keeps grinding the previous owner said the motor was newly rebuilt
it had a busted case on the c-6 transmission I thought tis was the cause of the starter grinding
I installed a new transmission casing c-6 and still had very bad grinding
after reading this post I seem to think the flexplate my be wrong one for the D9TE 460 block --c-6 application
the existing flexplaet has no markings on it

How do I match this block casting D9TE 460 with the correct flexplate for

I found that my problem was with the flexplate, once you bust a couple teeth off the plate it's just a matter of time before they've all been ground off. You will definitely have the D9 externally balanced crank in your motor because it is far too much of a pain in the ass to even try to get the older (internally balanced crank) to fit inside the D9 block. Get a good replacement plate and swap em out, the plate is pretty cheap but replacing it is quite the pain in the ass, good luck!