I recently bought a 68 highboy with a 70's 460 dropped into it, when I bought the truck it had a new starter in it, the starter looks like the right one, but it grinded on the flywheel and wouldnt turn it. After addressing a voltage drop issue between the engine and negative terminal the starter would turn the engine but still seemed to grind while doing it, and after about 3 or 4 times of doing that the starter would just spin without touching the flywheel at all. I'm wondering if the starter on it is bad even though it's brand new, or if anyone has any other ideas of what the problem may be. Thank you

 

Maybe it had a new starter because there is an issue with the ring gear?

I know the later ('92 & up) 460 pmgr starters were different for manual and automatic applications, but '70's 460's were all automatics and the old style starter's bendix doesn't seem to care.

​​​​​​​Is the indexing plate in place?

 

There doesn't seem to be an indexing plate anywhere, I tride a newer pmgr starter for a automatic and it didn't connect with the flywheel at all. The transmission is a 4 speed manual, I belive a np435 if that makes any difference. Also I didn't notice any damage on the ring gear even after the starter grinds

 

Ah ha!
Are you sure there is no metal plate sandwiched between bellhousing and block?
(because this is what provides a positive location for the starter in a 460)

Can you read the block casting number up by the starter?

IF it is an internally balanced engine (engineering number *before* D9TE) then someone has had to install an FE 390 flywheel and a 351M/400 bellhousing.
... well they could have installed the $500 L&L zero balance STI cert. 460 swap flywheel, but I doubt it.
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460's didn't come with a manual until hydraulic clutches in 1983.

That may be the issue

 

I've got a few 390's laying around and I was going to put a starter from one of them into it but the bolt pattern is different, as the FE block starter takes 3 bolts, and I can't ask the previous owner about the truck or how the engine was swapped into it

 

Upon closer inspection the ring gear is more damaged than i thought


Here's a few pictures. I'm assuming I have to remove the starter to see the casting #'s?

 

I just rolled the engine over manually so that the starter would connect with a different spot on the ring gear, and it grinded, but turned the engine a little bit before going back to spinning, I'm beginning to think it's the ring gear on the flywheel that's too worn down to work

 

I had starter problems when i switched from a T-19 to a Zf-5 gearbox.
Went through 5-6 starters before I shifted the starter closer to the aftermarket 5 speed flywheel by slotting the lower starter hole and using a grade 8 flange bolt to clamp it in place.
For me the teeth weren't meshing deep enough and would cam out, in some cases breaking the snout right off the starter.

I can't imagine you don't have enough depth of throw when you're already missing the plate but I have never compared a 460 and 390 flywheel side by side.