damac

I am getting the parts together to build a 406 for my 65 coupe. I am planning on swapping most of the parts over from my 327 (RPM intake, World sportsman ii heads, MSD, etc...). I currently have a Holley Streeet Avenger 670cfm carb and I am wondering if this is enough carb for a 450 hp 406? I have seen some 383's make good HP with 650 carbs, but most of the 406's I see are running 750 or bigger carbs. I am not going to run too agressive of a cam, but I am looking for the maximum HP and torque in a streetable motor.

If I do need a bigger carb, does anyone have any suggestions on which carb to go with? I was thinking of the Hollye Steet Avenger 770, but they are kind of spendy.

If anyone is interested, I may have a nearly new 670 Holley Steet Avenger carb for sale cheap.

Thanks,

Mike

Crazyhorse

You'll definitely want the bigger carb for 450hp :yesnod:

67ratrag

What is your redline? Need this to calculate the minimum necessary CFM for your engine.

damac

67ragtag,

I think the redline for a 406 will be around 6,000 rpm.

Mike

Vetterodder

I also think a bigger carb would give more power on the 406 but it wouldn't be under-carbed with the 670. While the larger carb will most likely give more high rpm power, the smaller carb will probably give better throttle response at low and mid rpm. I'd be inclined to try the carb you already have and see how it feels. If you decide you want more power, and don't mind spending the money, a new carb will still be an easy swap.

DZAUTO

NOT EVEN CLOSE! Now, if you have this engine in a 75 Caprice wagon, it will be fine. But for 450hp from a 406ci engine? Nope.

67ratrag

A 406 at 6000 rpm is moving 704.86 cfm of air volume through the engine. A 670 cfm carb falls way short and cannot feed this size engine at that rpm. I would recommend a 750, and you will have to change the jets as per your requirements.

StrayDog

750 cfm minimum needed for good throttle response ,,, , reccomend the 750 demon ..I have the stock HOLLEY 780 cfm ..it is tired , like me ....... can use Viagra.... but the Vette needs the 750 demon ,,, minimum, will be putting a 750 demon with vac sec on my 427 this winter.....if you have stiff gears like 411 go with a 800 cfm double pump Holley.,,,,,just my 2 cents.,,,,,,,,others will have different advice ....WOOF WOOF


[Modified by StrayDog, 6:14 PM 11/17/2001] :chevy :seeya :chevy :chevy :chevy :chevy


[Modified by StrayDog, 6:15 PM 11/17/2001]

Ganey

You might get by if on a single plane. Get a 750. A good 383 needs a 750.

:cool:

damac

Thanks for all of the advice,

I definitely think I will need a 750 or 770. I am leaning towards the Holley Street Avenger 770 because it is easily adjusted and I plan on dyno tuning the motor. I don't know anything about the Demon carbs. What is the main difference between the demon and the holley? How much would a demon cost and which carb is better for a (almost) daily driven car??

Thanks,

Mike