66 Hemi jetting

[RJRENTON]

The low speed jet is part of the primary booster venturii assembly in both rear (primary) carb and the front (secondary) carb is NOT readily adjustable....the fuel metering orifice can be enlarged slightly but reducing it requires resoldering it and redrilling smaller....not recommend. Just my opinion.
Bob Renton

 

[AR67GTX]

I’m pretty sure a 380 Jet a .080“ jet. I have been sitting all of my carb float levels just a little below spec, especially Holleys, to help minimize ethanol percolation. I shouldn’t think 1/32” low on the float would be your problem. I could be wrong.

 

[AR67GTX]

I just stumbled upon this thread and all of the useful info that @Dragon Slayer has given. My 1966 Hemi (automatic) has an issue where if I'm slowing down and taking a turn onto another street, the engine runs rough & wants to stall, so I have to two foot it until I complete my turn. After a couple seconds, it clears up. To me, it seems like it may be flooding out.

The car had a big cam I it when I bought it, but I got rid of that and installed a stock street Hemi cam. My thoughts are that the jets were changed when the big cam was installed, or the floats are too high. Being that it's winter now and having nothing to do today, I took the carbs off this morning and took out all the jets. The metering rods check out to be stock as do all the jet sizes except for one. See below .......

View attachment 1402566

Is this 380 jet the same as the .080?

I checked the float heights and they were at 8/32" & the float drop is 3/4". My 1969 service manual says the float height should be 9/32". Would 1/32" high be enough to create create that condition?

Also, where is the low speed jet located?

Thanks in advance.

Did you check your floats to make sure both were dry inside - not leaking? I‘m not sure what might cause a Carter to act up in a turn other than the fuel level getting too high and sloshing out of the bowl vents in a turn. Might take a close look at the needle and seat to see if it might have a sealing issue. Also PM Dragon Slayer as he’s definitely the Hemi carb whisperer.

 

[Dragon Slayer]

Yes 380 is .080 so your jetting and rods look fine. As Bob stated idle jet on primary venturi. Picture shows it as idle tube.

Is there pooling of liquid fuel inside carb? Venturi gaskets good, screws tight? Intake stock, not vanke modified? Possible a float is high and your spilling fuel into intake on a turn. The lower the float measurement per manual, the higher level in bowl will be. The front carb setting is 19/64" and the rear is 7/32" with viton/flare needles.

So your 8/32" seems fine unless a seat is leaking. Does it do it in any turn? Or just left or right?

 

[AR67GTX]

Ohh - I see I screwed up my response on the float setting - your a hair high instead of low. I wouldn’t think that should be a major issue but for what it may be worth I have been trying to run the fuel level in my carbs a little lower than spec. ( like /32“) because it seems to lessen percolation problems (my theory and observation).

 

[mrhemi]

You didn't mention this, but another thing to consider, are your carbs balanced correctly as per the service manual? You mention a '69 service manual. The procedure for carb balancing in that manual works very well (idling on both carbs, not solely the rear). It is particularly important for off idle performance but possibly may come into play in cornering issues as well.

 

[Richard Cranium]

Yes 380 is .080 so your jetting and rods look fine. As Bob stated idle jet on primary venturi. Picture shows it as idle tube.

Is there pooling of liquid fuel inside carb? Venturi gaskets good, screws tight? Intake stock, not vanke modified? Possible a float is high and your spilling fuel into intake on a turn. The lower the float measurement per manual, the higher level in bowl will be. The front carb setting is 19/64" and the rear is 7/32" with viton/flare needles.

So your 8/32" seems fine unless a seat is leaking. Does it do it in any turn? Or just left or right?

View attachment 1402799

Thanks for the response. The condition seems to happen turning in either direction. Stock intake & cam and all screws are tight. Hadn't looked for any fuel pooling. I'll get a couple of carb kits and replace the gaskets and needle & seats and go forward from there.

 

[Ceedawg]

Thought I’d add what my two has in them, pretty sure it is the Chrysler race upgrade kit, I’ll be leaving them like they come, I also have a stock front one to go by if they don’t work well. 4139s and 4140s k5 build.
The boosters have no snivies.

 

[Ceedawg]

Stock front 4139-s c6

 

[Dragon Slayer]

The Race set up included larger jets and different rods and was meant to be used with a Vanke Modified manifold for racing. So distribution was different. You have a miss match of parts. Street 66 jetting with emissions rods from 69 up carbs. With Vanke mod primary boosters. If your using a street manifold your distribution will not be optimized.

 

[Ceedawg]

Maybe whoever found those rods worked better for whatever combo they had at the time? Way to many years have went by and these looked at least 30-40 years since they were used. Once I get it running ?? I’ll know a little more.
BTW this engine will not be stock by any means.

 

[Dragon Slayer]

Or they could not get the original rods and used the latest ones. Or they had pieces of hemi carbs and the slapped it together because they were valuable. Who knows, but the jet/rod combo is in the lean direction and what the emission set up used. The race manual will give you the setup that Chrysler testing found to be the best combo.

 

[Ceedawg]

Or they could not get the original rods and used the latest ones. Or they had pieces of hemi carbs and the slapped it together because they were valuable. Who knows, but the jet/rod combo is in the lean direction and what the emission set up used. The race manual will give you the setup that Chrysler testing found to be the best combo.

I have the Carter strip kits to pick from.. jets, rods, springs, needle and seats. In the 70s these carbs where plentyfull, a racing buddy had 4 complete sets (intake, carbs and air cleaners) on the shelf I could of bought for $20 each. Dummy me I passed, I had nothing to use them on. He would buy the Hemi car use the engine and junk the car. He said the most he paid for a car was $900. Good times back then

 

[Dragon Slayer]

You guys were lucky, old racer speed shop owner would throw away manifolds and such because customer didn't want it and not enough storage. Plus the customers that said get that hemi out and put a 440 in. G