horrible starter / flywheel problem please help!

i bought my 78 blazer with the problem that it screeched when starting it but i figured all it needed was a couple of shims to adjust the starter but then it got worse to the point where it would make a horrible grinding sound and wouldn't turn engine over.  So i try shiming it and it dosnn't work.  Then i go buy a new flywheel and starter, install them today and crank it, everything started just fine no more screeching, i start 3 or 4 times with no problems then i leave the truck for about 4 hrs and go back to start it and i have the same screeching noise i had when i bought the truck.  So i put in one shim and schreeching happens then another shim and more schreecing so i put the starter back in with no shims and same problem.  Then my dad suggests i grind the starter so we do that and put it back in, this time the truck still scrreches then starts.  After that i turn it off and try to turn it back on but get the worse screeching that wont turn over the engine.  What do i ***  with each try my new flywheel keeps getting beaten up by the starter.      
solid axle chevys cant be beat
78 K5: 350 V8,700r4,np208, 8 lug D44 4:88, 14 bolt 10.5 4:88 with detroit locker and 35 inc parenelli jones dirt grip tires

There were some issue with starter clearnce in the 70's with GM starters. Make sure you have right starter and flywheel and I also suggest that you do not have correct shim combo and shim it from the start because new starter may be damaged now. Also if battery is weak or cables are not heavy enough, the current make not be strong enough to positively engage starter.  

how do i make sure the parts i got from napa are correct even though i gave my exact vehicle info?  I keep trying differnt shim commbinations with same screeching except one time it actually started the motor. what do you mean by starter clearence problems in the 70s?  Did alot of people have this isssue regardless of how many times they tried to shim it.  
solid axle chevys cant be beat
78 K5: 350 V8,700r4,np208, 8 lug D44 4:88, 14 bolt 10.5 4:88 with detroit locker and 35 inc parenelli jones dirt grip tires

The "fix" from GM was to shim it. I was driving then and I forget if it was a block casting issue or starter issue or both. I had a friend with a 69 327 that had to be shimed whenever you changed the starter. It got worse when engine was hot and it expanded.  

ok i guess im going to have to just keep trying to find the right shim combination till it works.  
solid axle chevys cant be beat
78 K5: 350 V8,700r4,np208, 8 lug D44 4:88, 14 bolt 10.5 4:88 with detroit locker and 35 inc parenelli jones dirt grip tires

Geo450racer:
ok i guess im going to have to just keep trying to find the right shim combination till it works.

Yes, that is the "fix"  

I don't think this problem is limited to the 70's, unfortunately. I've seen it happen on anything from a '57 Chevy on up.
When you're experimenting remember that you should never use more than 4 shims, and that sometimes you have to shim the two bolts unevenly.  

Dirty_Dog:
I don't think this problem is limited to the 70's, unfortunately. I've seen it happen on anything from a '57 Chevy on up.
When you're experimenting remember that you should never use more than 4 shims, and that sometimes you have to shim the two bolts unevenly.

It was biggest problem is 70's with a few issues in other model years. The uneven shimming is not a bad tip but generally you want to keep the difference to about two shims tops because it can cause bolts to bind and not clamp as well either. (one shim difference is fine)  

Thanks guys but i finally got it fixed!!!!!!!!!!!!!!! all i needed was a half shim on one side. You shoudl have seen my face of relief when i turned the key and heard the motor turn over like it should.          
solid axle chevys cant be beat
78 K5: 350 V8,700r4,np208, 8 lug D44 4:88, 14 bolt 10.5 4:88 with detroit locker and 35 inc parenelli jones dirt grip tires

Good deal, I would also suggest that if you ever have starter problem in future, rebuild the one you have as you know its fit now.  

What you need to do is get a 1/8in drill bit put it between the top of the flywheel teeth and the shaft of the starter"what the bindex slides on"and shim it too it.You do that and it will give you no more problems,you want a 1/8in gap between the flywheel teeth and the shaft in the nose cone