In the process of adjusting my valves. Shop manual says to turn engine to get the line on harmonic balancer to match to zero with #1 valves not moving. This should be #1 TDC comp. Did this and checked distributor pointing close to #1, seemed good. Adjusted intake and exhaust valves per manual. Then rotate 360 degrees to get the line to match zero again and this should be #6 TDC comp.

Here is the question: I am rotating using the nut on the harmonic balancer and a breaker bar. The engine has been rotating ok except now I am at around 12 degrees on the tab and she is not turning anymore, the bolt is turning. Concerned that I may be over tightning bolt and break off. Can I crank short bursts on starter to get there (with ignition disconnected)? (my coolant lines are currently not connected) or is there another way? I plan to loosen the valves of the ones that are left to adjust first in case they are already too tight and recheck with a torque wrench on the harmonic balancer to see where I am at. Thoughts?

Which way are you turning the crank? You should be turning it clockwise, looking from the front of the car. If you are turning it c-clockwise, then you are loosening the bolt.
If, in fact you are turning it clockwise, then I would suggest you replace the bolt, anyway, as it will probably fail at the worst possible time. It may be that the bolt is stretching, or it could be stripping the threads. Either scenario is bad!
You can bump the engine over with the starter, no problems there.
Also, if you leave all of the sparkle plugs out, it will be much easier to turn the engine.

If you take the plugs out, you should be able to turn it either direction. I have an after market balancer on it, and one of the treads I read recentally noted that some balancers are deliberatly 10 deg off. I wanted to check mine, which I thought was on the money. I have a piston stop that treads in the plug hole, removed the plugs and checked it, which was ok. With the plugs out, it turned either direction with a 1/2 in. ratchet.

Dave

Taking the spark plugs out -  good idea, done.

I am using the shop manual method for adjusting the valves: set #1 TDC with mark at zero on timing tab, check distributor pointing at #1. Adjust Exhaust valves 1,3,4,8 and Intake 1,2,5,7 then turn crank to #6 TDC with mark at zero on timing tab and adjust the remaining valves.

Found the problem, well sort of. She turns fairly easy but stops at 12 degrees before the zero mark. Found that if I loosened the first 8 valves that I previously adjusted she turns fine. So this time started at #6 and had the same problem when I tried to turn crank to #1. At 12 degrees or so, will not turn anymore. So loosened up the 8 valves I just did and tried the Haines manual method using the 90 degree method starting from #1 set intake and exhaust than rotate 90 degrees set the next in the firing order. Same problem after I got half way through the order, #6 stopped about 12 degrees before the zero mark.

For adjusting the valves I am turning the rods until slight resistance is felt then tighten 3/4 more turn.

Something is fishy in Denmark!

Either I am doing something wrong after following the shop manual and the haines manual or I am beginning to think something else may be wrong/broken. THoughts?

I'm gonna go WAY out on a limb here...
Try adjusting one cyl. at a time, and turning the engine over 2 complete turns after each adjustment. This will give an indication of which particular cylinder is the source of the "lock-down".
When you find the one cyl./valve, check very carefully for a broken valvespring, or possibly a "coil bind" on one of the springs on that cyl. There should be NO touching of the individual coils on any spring in the fully open valve position.
It is very possible that you do actually have a bent/stuck valve. See if you can determine which cyl./valve is creating the problem.
If you can back off on all of the adjustments, and the engine will turn with no problems, I have to think the problem lies in one of the valves/springs.
Sorry!! Wish I had a better idea!

If the engine was running ok befor this, it's a difficult situation without being there. I pretty much agree with Joel. Another thing to try is to back off all the valaves, adjust one set,  (half the valves) put the cap back on and turn the engine by hand, of course. When you encounter the problem take off the cap and see what cylinder is about to fire. Back off those pushrods and see if it turns then. I don't belive a hydraulic lifter is locking up and causing the problem, more likely a valve. Keep us posted.

Dave

FLA VETTE, Bernie, and I spoke on the phone today.  I got additional info.  The engine stopped when it spit the timing chain, at about a steady 3000 rpm.   In a small block chevy, this would not hurt the valves.   BUT....  a couple of years ago the valves were done.  If the heads were shaved due to warpage, the clearance may have been reduced enough to cause a valve/piston clash.   He might have a bent valve.   After some more research, we will know more.

Anything's possible, but with a dish piston, I still think it would be a stretch. Stranger things have happened!! I'm anxious to hear what the source of the lock up is. Will stay tuned in...same Bat channel...same Bat station...

My spec book says the 80 L82 has forged aluminum flat head pistons. The heads were reworked 2 years ago but not for overheat just for cleanup (had broken valve spring so figured it would be best to just have a full valve job done since she had 110K miles). Not sure how much they took off though.

Played a little more today, turns free unless #1 valves are adjusted. So it seems like something in the valve train like a bent valve, cam problem, or lifter problem.

So I am done for now working in the 95 degree garage. Since the heads have to come off, I am going to have a shop put on a set of new aluminum Edelbrock RPM heads, RPM Cam, and check the bottom end. Most likely pull the engine and freshen the bottom end unless they recommend otherwise. Then drop and freshen the trany while the engine is out.

I will repost in a few weeks what I actually find when the heads come off.

Thanks again, great comments, great advise, I learned allot.