Grinding starter after flex plate swap

[Eoth]

I swapped my 302 for the Explorer 5.0. Now my starter makes a metallic grinding noise when engaged. It starts the motor fine and stops when I stop cranking. I imagine that it has something to do with some type of difference between the 28oz original and the new 50oz flexplate (FRA-214)????
I took the starter off and inspected everything an reinstalled (same effect).
BTW the transmission is a C4.
Looking at the starter gear I see that it is worn but I wouldn't call it "bad"... I do see what appears to be scraping on the edge of the flywheel teeth. It is just a worn in starter gear having issues with sharp new flywheel teeth?

 

[Eoth]

Anyone????

 

[Skiddy]

is the tooth count the same from the 28oz to the 50oz?
was the starter used on the C4 before?

 

[MDG_Bronco]

Does the flexplate sit at the same distance from the starter on the Explorer engine as it did on the 302? Maybe the starters reach is too far or too short now?

As Skiddy said, maybe the tooth count is different. I have a 1973 302 and my flexplate tooth count is 164.

 

[Eoth]

Both the old and new flex plates are 164.

 

[billtammy]

I can't tell which starter you are showing but use the explorer one. Also the nut shown for the torque converter is not the right one.

 

[gr8scott]

Had the same problem after my C4 was rebuilt. A friend of mine milled out a 1/16th shim plate that goes between the
starter and the trans. That fixed the problem. But yours looks like it isn't engaging far enough.
Is it hanging there by the wires? Might have someone bump the starter and see if the starter gear is extending all the way out.

 

[JohnJohn]

My thread may be helpful http://classicbroncos.com/forums/showthread.php?t=267858

 

[Eoth]

I always try to wrap these things up for people who take the time to do their own searching. It turns out that over time my old starter and old flex plate deformed each other enough that they became a "matched set". The slightly worn and deformed gears of the starter would not mesh correctly with the new flex plate. A trip to the parts store and 50 bucks I have a new starter with a lifetime warranty. Gears mesh perfectly and no grinding noises. Thanks for all the suggestions and support!!