Starter Grinding Intermittantly

I don't have to remove my longtube header to get the starter out, but I don't know about the tri-y. The starter could have a worn bendix gear, the flex plate ring gear could have the same, or the torque convertor drain plug isn't lined up with the access hole causing the flex plate to be warped.

Temporary fix

Mine does the same, there are always shims. Not a permanent solution, but it will work until you feel like pulling the transmission. Assuming of course, it is the flexplate.

Mine is the flexplate, put in a new starter and found the problem. The old gear was chewed pretty good, wore into place. Of course, eventually it wore so much it wouldn't catch.

Typical, everytime I open something up on this car, it's all worn to crap. Ask me how a bad timing chain turned into a new cover, balancer, water pump, bolts, etc.