what carb for my 400sbc?

[Moabdude]

I have a simple 400sbc with no major power modifications.

I like the Demon carbs but what model do i choose.

My main goal is to cruise around with a decent fuel milage.

Any suggestions?

[Shaker455]

Are you running headers and a alum intake?

I'd don't recomend Demons anymore as to there bad quality and extremely poor customer relations.

A 750 downleg would work nice....

[XTRMEASURES]

id say 750

[68Formula]

Are you running headers and a alum intake?

I'd don't recomend Demons anymore as to there bad quality and extremely poor customer relations.

A 750 downleg would work nice....

Ditto on all accounts.

[cad]

If you use a 750, use a vacuum secondary to get any mileage. If you use a 4150 (dbl pumper), I would recommend a 650.

[MonzaRacer]

I agree look at one of the HP holleys and I would go with at least a 750 vac sec, make sure you have the quick change sec cap on it and get the spring kit you can then make sure the secondaries come on like they should, not dumped on but gradual like.
You should never feel the secondaries open you should just feel the car keep pulling.

[Moabdude]

Thanks guys.
I do run an aluminum intake and headers.

so not a 650 but a 750. i always thought the 650 would be enough for my simple 400SBC.

would a Edelbrock 1407 = 750 be okay?

electric of manual choke?

[Djchunter]

I say 625 demon

[hotrdblder]

custom built, blue printed for your motor, most times dont need to touch them out of the box and they perform like no other carb you have ever had.
try pro systems or bo law products

[Rick Dorion]

I am currently using a Holley 700DP on my 410. It works like a charm. I used an Innovate to get it jetted appropriatley and am very satisfied.

[Shaker455]

custom built, blue printed for your motor, most times dont need to touch them out of the box and they perform like no other carb you have ever had.

Ditto on that, that's why I build custom Holley's built to the customers specs, live tested, then advise cutsomer's thru tuning stage.
The end product is a unit tuned to "ROCK"

[hotrdblder]

also the custom carbs are not much more then a demon or other.
i paid 830 for the pro systems hp1000 custom carb for the 496 bbc stroker i built for volt68s car here, did not touch it out of the box,
stock hp1000 is 650-700, so for another 130 i had a carb guru build it with free lifetime tuning over the phone. cheap money if you ask me

[TurboLark]

Are you running headers and a alum intake?

I'd don't recomend Demons anymore as to there bad quality and extremely poor customer relations.

A 750 downleg would work nice....

Heard the same thing. My carb guy is always complaining about having to fix demons all the time.
Find a used 750 for cheap and have a good shop do it up. I did that with a 700. $75.00 for the carb and 130.00 to tweak and rebuild for my application. I have a hard time buying a new carb anymore, as they all need to be reworked some anyway.

[Shaker455]

Hotrdblder,
I'm glad to hear you had good luck with Pro-systems.

I've had a lot of Pro-systems carbs come my way to be corrected as the cal was way off from the customers build sheet.

One in particular was a HP 1000 for a 408 stroker Ford in a Factory Five Cobra....

[1969CamaroRS]

I'd do a 650 Vacuum Secondary Carb and get a stub stack. Really need more info thou, Cam specs, Compression, Exhaust size etc...

[70camaro406]

My main goal is to cruise around with a decent fuel milage.

Do a 600-650 for that purpose. Edelbrock carbs are good for cruising/mileage too.

[4086D9]

Holley 3310 750....works great on my 408.

[70bird]

IIRC, the redneck formula to carb sizing for street/economy is:
Displacement X 2 = CARB CFM @ 100% VE. Of course it is not likely to have 100% VE, most likely around 80%

So, 400 - 20% = 320 X 2 = 640 cfm. If it has cam and headers go larger as VE increases, or smaller for fuel mileage. Just garage tech, can't even remember where I know it from. Probably PHR etc.

Mark

[nicks67camaro]

I'm running a holley 650 double pumper with mechanical secondaries. I had 750 on it but I had no noticable difference in power but a loss in overall mpg. The jetting is 68 and 72 (i think) oh the motor is a SB400 afr 210cc heads edelbrock victor Jr solid roller msd pro billet and 6a1.