A310 running rich

Hello to all. My name is Per Even, from Norway. I been lurching in this site for several years, not posting, but reading.
Now i have a problem with my a310 and are hoping someone can help me.
I have a stock 1981 a310 that started running rich, looking at the carbs and not finding anything i figured that a carb upgrade to a holley was the right ting to do (when something is broke upgrade)I got hold of a secondhand holley 390 and re manufactured a spare manifold. Installing this, trying to adjust but the car is still running rich no mater what i do. Any ideas?
Anybody set up a used holley? Witch nozzels do you use? What have you changed?
Btw dizzy cap, rotor and leads are new as-well as spark plugs, even tried an other coil.
The car revs willingly but runs rich at idle.

Before I done headwork on my one from memory the carb set up was The front jets were 34s and the Rear jets where 38 with the Second lightest spring for the secondary opening

Thank you for the feedback, carbs is not my strong side, and since the car is missing its mot it is difficult to take it somewhere to be adjusted. I am trying to get it to run well enough to pass the mot and them take it so someone that knows these carbs.

Just checked my carb. it has only one set of jets but i hope there are several different numbers for the same jets, because i bought a set of jets and the smallest one (the one i am running) is a 64.
But while I checked the car i noticed that the throttle plates for the primary throttle was not closing properly, a little adjustment later the carb was back on the car and it ran much smoother. Adjusted the idle to 900ish rpm and the mixture, so now it is flocculating between rich and lean (i only have a narrow band lambda). Will see if i can get a different jet later. But for now it is much better.
Did you get the idle down to 800 or what idle do you run, mine don't like 800 it is on the edge of dying.

Ok my engine is the 2.8 and you are 2.7 so your jets are way to big, frunt jet will be 32s, your carb has not got the additional plate fitted so you can jet the back barrels, you can get the kit from Holley carbs, then the rear jets will be 36s you will also need the diaphragm Spring kit. Also have you got the fule pressure right and set the float bowl fule level, this is V important as you will get nowhere unless it is right.

Sorry went down and had a look at my jetting box they are 50 not 30s, so 52 and 56.

maybe mine is right then, the original jet is 52 something, i will try that.

was back at the car, put in the original one (that came with the carb) they are marked 521 or something like that. but they are smaller then the 46 from my kit. The car did run very smooth on idle and i got it to almost be still at normal on the lambda (still only narrow).
Put inn a set of clean spark plugs and run it at idle and a little revs for about 10 minutes, pulling the spark plugs they looked fine no sooth and clean. Hope this is enough to get a MOT, the i will take it to someone that know these carbs.
Do you have any other tips about this setup that i should think about?
There was some mentioning about fuel pressure, i am running the original mechanical fuel pump.
By this i hope i am closer to this.

You must set the float bowl levels as it is very important, The carburettor is well oversized for the engine and when I did mine we got 154hp on the frunt barrels alone so I very much doubt that you need to set the back barrels, leave them as standard and put strong spring in so thay don't open.
The reason you need to put biger jets in the back barrels is because when they open the airspeed drops dramatically from the front because of this lower air speed you need bigger jets in the back so that the fuel can be drawn up easier to keep the air fule ratio correct, but your engine only makes about 145 and you can get over 150 on the fronts.

Fuel level was spot on when i first installed the carb, will try to put heavy spring on the secondary or just lock it to see what happens.
Maybe mine got a little over 150, i have a sett of simone manifolds and a free flowing exhaust. That should make it breathe a bit easier.