Carb suggestions

[richardmoparman]

Looking on a recommendation for the size Carb to use on my 73 Charger S/E.It has a 440 with a 484/284 Mopar purple shaft cam and has been Bored .30 over.It has .30 over pistons and a stock crank shaft.I am running a 2.76 Sure grip 8 3/4 rear end with a 727 trans.It will have 2.5 inch stainless exuast with 40 series Flowmasters.Will basically be a daily driver.I hope this is enough info to describe what I have and what I will need.Any help would be greatly appreciated.

[BSB67]

Is the car running now?  If so what are you using now and how does it run?

MP 284°-.484 is not a daily driver cam in my book.  If you have low compression and factory converter, it might not be idle and low speed friendly.  And if your not using headers, performance will be less than desirable too.

That aside, for a true DD, I would consider the factory spread bore or std Performer intake with a spread bore carb.

[ACUDANUT]

Holley 650-750.   Either way, you'll be happy. Stay away from thermo-junk and quad a-Junk.  You will be better off.

[aifilaw]

Anyone seen these...? I couldn't find any topics about them doing a search

https://www.holley.com/products/fuel_systems/fuel_injection/sniper_efi/

[richardmoparman]

Thanks guys.It is running.Engine runs and idles fine.I have headers on it as well.I have a 770 street avenger on it and it runs really rich.Have set float level and leaned it out but still runs rich.Was thinking less CFMs might help.

[Simonic]

[quote

MP 284°-.484 is not a daily driver cam in my book. 

[/quote]

I agree .

[BSB67]

770 is not to big. If anything I would put more on it.

When is it too rich?

[Bronzedodge]

If you get a set of 3.23's it will seem like a new car.

[richardmoparman]

It is running rich at idle.

[BSB67]

....Engine runs and idles fine. I have a 770 street avenger on it and it runs really rich. Have set float level and leaned it out but still runs rich.

It is running rich at idle.

Then I guess that it is not running fine at idle.

Do you have A/F information?  If not, it is hard to to tell if there is a problem and if so, how bad. If you have a stock converter, and it is idling 900 in neutral and 750 in gear, that cam is going to smell at idle due to its overlap.  Assuming that there is not something else wrong, like a vacuum leak or other carb issue, the things that you can do to help include setting your initial timing at +20°, increase IAB, decrease IFR.

From my experience the SA carbs are too lean to begin with on a warmed up engine with any cam in it.

A lean condition including those from a vacuum leak will cause a slight, almost undetectable miss at idle. If that situation occurs, your eyes will burn from the exhaust.  Most people mis-diagnose the condition and try to fix it by leaning out the carb.

[richardmoparman]

It is running rich at idle.

[XH29N0G]

Assuming you have adjusted the idle mixture screws for max vacuum, I would next check the timing as BSB suggested.  For my car, I found that adding timing made it possible to set the idle less rich.  I have an A/F gauge installed so can see it.  I did have to change the IAB and IFR to get the screws set in correctly.  I have a different carb, but the principles are the same.  I also agree that changing the carb size will not change whether the carb will idle or not and that a 770 seems like a reasonable size carburetor for your car.  And I will reiterate the issue of a lean top end.  I ran a SA a few years ago and it was very lean up top (to the point of backfire).

[garner7555]

If you don't enjoy tuning a carb, then consider EFI.   I just started up my FiTech last week on my 440.   It's basically an electric Carb, that will tune itself one you plug in the right info into the computer.     

https://www.youtube.com/watch?v=PCdYUiGa4ys


P.S.   I pulled out a new purple shaft .484 cam due to low vacuum, it's really not a friendly cam if you pair it with power brakes.

[Nacho-RT74]

Holley 650-750.   Either way, you'll be happy. Stay away from thermo-junk and quad a-Junk.  You will be better off.

So not just the 71/72 vs 73/74 war but also the carb war? LOL

A well tuned TQ will outperform any other carb around. The hard part is get one in perfect conditions and tune it nicelly.

In similar setup than a TQ, a Demon 750 cfm with plastic bowl could be a nice options as far I have read.

Stock 440s on 70s run 850 cfms TQs

[69wannabe]

....Engine runs and idles fine. I have a 770 street avenger on it and it runs really rich. Have set float level and leaned it out but still runs rich.

It is running rich at idle.

Then I guess that it is not running fine at idle.

Do you have A/F information?  If not, it is hard to to tell if there is a problem and if so, how bad. If you have a stock converter, and it is idling 900 in neutral and 750 in gear, that cam is going to smell at idle due to its overlap.  Assuming that there is not something else wrong, like a vacuum leak or other carb issue, the things that you can do to help include setting your initial timing at +20°, increase IAB, decrease IFR.

From my experience the SA carbs are too lean to begin with on a warmed up engine with any cam in it.

A lean condition including those from a vacuum leak will cause a slight, almost undetectable miss at idle. If that situation occurs, your eyes will burn from the exhaust.  Most people mis-diagnose the condition and try to fix it by leaning out the carb.

I agree here, the street avenger carbs are usually lean out of the box, had a 670 on my 383 and had to jet it up quite a bit to get the lean stumble out of it. Think it was three or four jet sizes and it ran great after that.

The 284/484 cam will need a good 2800+ stall converter and healthy compression to run good. And all the rest that is said here about base timing and etc....
I like the old purple shaft cams but they are a bit big when you see the spec's at 50 degrees. They are very good strip cams for a hydraulic flat tappet but not so much as a street cruiser IMO.....

[ACUDANUT]

 I am a believer in the Holley 750 !!