Slop in original timing chain on 78k 430

I'm not finished tweaking yet or at least I don't think I am and am still learning. Probably 90% of what I'm learning here is new to me.
I still want to see where the timing is at all in, I'll get there. I value your input.

 

I got energetic when I got home from work tonight. Buick up on ramps and 30* marked was added to the balancer. Then I got junior to run the throttle for me.
Here's the data I collected,

Vacuum advance disconnected:
All in at 2000 RPM the best I can guess is 20* because of where the mark is, it's passed the degree gauge.
Rev'd to 3000 with no change from 2000 RPM.

Vacuum connected (TO MANIFOLD):
550 RPM 12* (IDLE)
2200 RPM 32* (My average cruising speed)
2500 RPM 34*
2800 RPM 36* all in

Keep in mind this is a driver, I never race it, it does flex it's muscles often though.
What's your opinions, respectable, use lighter springs????
My tach sits at 2200 @ 55 mph 90 km/hr for me. The highways around me are 50-55 mph 80-90 km/hr.
It's been so long since I've been on the 401 with it, 60 mph 100 km/hr that I think my tach sits around 2400-2500 RPM.
I'm curious to see if the vacuum advance hooked to the manifold affects the engine temp (cooler) next summer. Not that I think it's getting to hot, but this year it did run about 3* hot on the highway than it did in the past, in town it was happy at 195* just like years past. There was one change I forgot about, with the rebuild I'm now running 430 heads. This engine is running s much better since the distributor was worked on 4 years ago.

 

Sorry Larry I didn't specify which timing mark went past the timing tab, it was the initial timing mark that was beyond the timing tab. The new 30* mark hadn't made it's way up to the tab yet, probably 10* before 0 mark on the timing tab.
I would say it's a 16* timing tab, the tab has 0, 4, 8, 12, + indicated on the tab with a shorter indicator between for a 2* mark, but past 12* there are 2 more indicators for 14* and 16* as the final mark. Image included.
I hope this clear things up and it makes sense.

Vacuum advance disconnected:
All in at 2000 RPM the best I can guess is 20* read from initial timing mark because of where the mark is, it's passed the degree gauge.
Rev'd to 3000 with no change from 2000 RPM.

Vacuum connected (TO MANIFOLD):
550 RPM 12* (IDLE) read from initial timing mark
The following are read from new 30* mark
2200 RPM 32* (My average cruising speed)
2500 RPM 34*
2800 RPM 36* all in

 

If its 20° all in timing is retarded.

 

Ok I'm following you now, I was going by the manual, letting the engine idle with the VA disconnected and setting the timing at 0* then letting the VA advance the timing. So forget all that and set the all in timing with VA disconnected and don't worry about the idle timing, it'll be wherever it is, maybe 20* advanced with VA connected. All we are looking for is all in timing, with VA disconnected using the 30*mark. So I guess the timing is retarded....whew you making my head spin with all this new info. I'll try to get it done this weekend.
I'm going by 36* advance because the cam weight base assembly in the distributor has a 36* advance slot in it. So I've always figured I have 36* of advance.
Thanks for your patients and explaining everything, I've just never done this kind of tuning before.
So I guess I've been robbing the engine of HP all these years. And here I thought it would go like a scared cat before.
I'll see what it does after this adjustment.

 

"All in" by 2000 rpm is a red flag for me.

That's nowhere near enough, and way too early.

32-ish degrees at 3000--3200 would be better.

If this were me, I'd have tested to 4000--4500 rpm. A distributor machine would be recommended.

If you had ~36 degrees at 2800 WITHOUT the vacuum advance, and then added the vacuum advance on top of that, I'd think you'd be better-off. But depending on gearing, vehicle weight, octane rating of the fuel, altitude, and a half-dozen other factors, that may or may not be too much centrifugal advance and still a little early.