it's Steves 260z... I visited with him and we had a blast tuning it.

The PO left us scratching our heads/ cursing many times....for example the locking nuts on the rocker (lash) adjuster pivots must have been 100 ft-lbs... some were so tight it took two of us on a wrench to loosen.

The vacuum advance canister had a leak so there was no vacuum advance; only mechanical. This makes the 32 degrees observed [AT IDLE] even more difficult to accept.

I don't recall spraying the starting fluid around the rear carburetor. I did the spraying around the front carb before Philip did the valve adjustment. I'll take some contact cleaner to the timing light, too. 

I had to put my 17mm crows foot on an impact wrench, compressor at 130 psi, then use a propane torch on each and every one.  I don't think the valves had been adjusted since new, 1977.

Did you do before & after measurements, Cliff? I'd be curious about how far out of adjustment yours got to be.

It's like taking before pictures, I don't think about it until it's too late. 

So, here's the update. I replaced the plug wires last night and ran the engine today. I found the rear carburetor wasn't pulling as much air, so I increased the air flow to match the front. I did a test that Philip showed me that he called the "equally $h!++y test" and found the rear carburetor was pulling its own.

My previous post was a little premature. I played with the timing some tonight and went to re-tune the carburetors after dropping the timing down. The rear carburetor was weak again. Following Mr. Warner & Mr. Pilgrim's suggestion, I attack the rear carburetor with starting fluid and heard the RPMs increase when I sprayed around the insulator between the manifold and carburetor. All four nuts were loose. I tightened the nuts and finished adjusting the carburetors. The rear behaved much better.

Good feeling, isn't it!  I'm having a blast tinkering with mine.

 

I've got Memphis on my mind.

Great detective work!  Resolving the bugs one at a time.

So I wonder in these instances of carb balance issue if it would benefit to isolate them better by removing balance tube and plugging the intakes ?

I think that is a great idea.  Passini hates balance tubes and states they do more to adversely affect performance (on webers). 

It has sparked debate on the triples about the balance tube and tuning with it attached. I set my triples without the balance tune first, then I balance with it installed . I would think in most cases with SU's it would not be necessary , but in a weird deal like this it might be required.