Running rich

[wantone]

Hi All,
   I'm running a 383 automatic 727a... Currently has a  4 barrel Holley 3310 with 73 jet and 6.5pv ... Manifold vac 15-16 at idle and about 12 in gear.  Cam - int262 ex270   lif462 exh470  110lsa. 

The thing smells like a gas station when running and i'm not sure how to adjust it from running so rich.    Any ideas or adjustments I can make?

[js29no]

 

[wantone]

OH YA - I'VE GOT ABOUT 18' IN THE TIMING

[HP_Cuda]

Well I'll take a crack at it.

Info on your 3310 carb:
http://1970mgr.org/_HolleyCarbs.htm

The secondary metering plate 134-21 is equivalent to a 74 jet.

I'm a bit suprised that you are losing 3" of vacuum when you put it in gear. But okay, let's stick with the 12" vacuum number. The next step down in PV is 5.5 but I don't think that's the problem. With your cam selection maybe the jetting is a bit rich so take it down the primaries to a 71 jetting and see what happens.

My other question is - where is your idle mixture screw setting at? Stock should be 1.5 turns out - if you are further out than that you might be getting some richness there.

Another good vid on setting idle mixture on a holley:
https://www.youtube.com/watch?v=UPGLUsW5ZeE

[Chryco Psycho]

Start with tuning it , float level , mixture screws , look for fuel dripping into the booster if this seems ok
I think you need to open up the carb & look for bad power valve or bad gaskets inside .
There is a tuning guide in the archives too .