GT 1600 Jr. M tuning procedure (longish)

[Jacob Haagerup <digest@xxxxxxxxx>]

So, after its 1.5 year hibernation my GT is finally about to be back on 
the road. I went to have it checked in order to get license plates on 
it and it failed. Most of the things were minor - a little weld here, a 
couple of clips for a fuel line there etc.

However, the guy shoved one of those emissions testing things up my 
tailpipe - ehrm, that of the car I mean - and it almost went off the 
scale. The car was admittedly not running at its best and the result of 
the test is that CO is way high and HC(?) too meaning that it's running 
rich and emitting unburnt fuel.

Before the test having gotten my 1 day permit I took it for a little 
trial run and had it up to 150 Kph on the motorway - just to get the 
cobwebs out. I would consider my run a reasonable Italian tune-up.

So my question to the esteemed listees is: How do I go about getting it 
to run properly?

Facts:

The engine is a 1.8 L out of an Alfetta with 40 DCOE Webers and 
basically stock.

Ignition timing is spot on according to the marks on the pulley and the 
advance is good. I have Golden Lodge sparkplugs and they DO tend to get 
fouled with a black deposit - always have but that is probably made 
worse by modern fuel.

I measured the valve gaps and they are slightly too tight - I believe 
in the .35 mm range on the inlet and .45 mm on the exhaust. Cam timing 
is spot on.

The engine runs with a lumpy or uneven idle which basically makes the 
whole car jump and shake. At speed it sounds a little harsh - more VW 
than Alfa.

Questions:

It's obvious that I need to lean out the idle. I was working somewhat 
on this yesterday and the optimum setting on the carbs is now leaner 
than it was - so far so good - but the engine still ticks over lumpily. 
Is there basically much more to do on the Webers? I reckon the jets are 
right and if so there isn't much more in it, (besides synching them of 
course), right?

Does the fact that the valves are tight have much influence on the 
emissions? What happens when the valvetrain wears - do the gaps get 
smaller or larger normally?

I figured that hotter sparkplugs might be a good idea. I understand 
that there are NGK 7s which are better. Would that help?

Any other things I might consider and should do to get things ticking 
over nicely, smoothly and powerfully, oh and ultimately cleaner?

Any and all hints appreciated.

Jacob Haagerup
1975 GT 1600 Jr M 1.8
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