[Tom Vaught]

Tune-up for a 9381 (830 cfm) 4150 Carb As every engine is different these are just common mods for that carburetor)

1) Remove the Rear Power Valve, Jet that side up 8 jet numbers (you can always drop them down a number or 2 later) and add the Jet Extensions I have mentioned in the past along with the Whistle Mods.

2) If the carb already has "Screw In" Air Bleeds you are good to go, otherwise you need to remove the pressed in bleeds and tap the holes for either screw in Holley bleeds or short stainless (drillable) set screws.

3) The Idle Feed Restrictions (which I talked about in the past) need to be in the "lower position".
Drill out the upper IFR restrictions to .100" for free flow to the lower IFRs.

4) Many times you can go from the .037" - .038" IFR to a smaller IFR sometimes as low as a .032 IFR.
If you need more you can always slightly increase the size. Making a hole smaller is TOUGH, LOL.

5) You can also increase the stock Idle Air Bleed to .070" and leave the Primary High Speed Air Bleed in the .026" or .027" stock diameter.

6) You can leave the Power Valve Channel Restrictions at .067" but if your carb has .059" Restrictions you can open them up to the .067" number

7) Primary Jet should be 73 (if you have it or 74). Secondary Jets should be 85 or 86 Jets.

8) Stock Squirters should be .031" and you can leave those alone.
Blue Cam on the front and stock rear accelerator pump cam on the rear.

9) Primary Jet should be 73 if you have it or 74. Secondary Jets should be 85 or 86 Jets.

10) You want a smooth idle in gear about 13 - 13-2 to 1 Air/Fuel Ratio.

11) Cruise Air/Fuel Ratio in the 14.5 to 14.7 Air/Fuel Ratio area.

12) WOT in the 12.6 to 12.9 Air/Fuel Ratio area.

Depending on what Pump Cam is on the Secondary might require further tuning (later opening preferred).

This carb should be happy on a small 240 degree roller cam with 10.5 compression ratio. A bit less CR will probably still be ok depending on the quench distance (piston to head). People are starting to pay attention to that more (finally).

You want the normal 18-20 degrees in the distributor with about 16 degrees initial. But see what it likes.

Real simple calibration which should run fine once you move the Idle Feed Restrictions, open the upper restrictions to .100" and mess with the Idle Air Bleeds. On Cliff's 4781-2 old 850 carb he had to go up slightly on the Idle Air Bleeds but later when the carb was on the engine on the dyno they said don't ever touch this carb, it is perfect.

On the old carbs sometimes minimal changes are ever needed to be spot-on.

Tom V.

I am not going to provide a Generic Dominator Calibration as there are a bunch of them out there and Jeff (Shaker455) does a fine job on Dominator Carbs.