which carb... advice needed 750 or 670?

[Andyw]

Well here is the run down for my 72 Roadrunner.

Stock rebuild on a 400 with 906 heads
3:23 gears
2800 Fairbanks stall convertor
Edelbrock dual plane intake
Hedman Full legnth headers
2.5" exhaust
Purple grind 282/484 cam

The car is basicly just a cruiser and occasional burnout 0-60 car. I know everyone runs a 750 without any issues but I can get a preety good deal on a Holley Street Avenger 670 #80670. From doing the RPM calculations ect it says it should be good but I dont want to run out of fuel yet I like the idea of a more torquey carb. Why cant I have it all? lol

I know a 750 will work so I guess what I'm asking is will a 670 do me well for my specific build?

 

[super-bee_ski]

650 is sufficient.
"most" folk always overcarb.

It depends on your "recipie"
I believe "Stock" 440s came w/ a 750.

Again, it depends on your recipie, another words:
Cam
Intake
torque convertor
exhaust
etc

Call Edelbrock's "TECH-Line"
That is what they are there for.
Tell them your application and they will help you.

Edelbrock Tech Services:
www.edelbrock.com/automotive_new/misc/company/contact.shtml‎Cached
SimilarEdelbrock, LLC Headquarters 2700 California Street, Torrance, CA 90503. Phone: 310-781-2222. Fax: 310-320-1187. Tech Line Only: 800-416-8628.

 

[Andyw]

lol, sometimes the obvious answer stairs right at me blankly. Thanks for the advice! Im on it.

 

[67 coronet]

by the math a 600 can run your eng combo up to 5000 rpms.go with the 670,save the money!it will creat more then enough power with what you have.

 

[Charger686970]

just my input if it helps, but i would go with the 750cfm vac. secondary just because the factory rating on most 400-4bbl and 440-4bbl used a 800-850cfm thermoquad depending on application and that was a stock engine. you have a slight cam, more torque converter, headers and aftermarket intake. if a engine shop built the motor for you did you ask them? either size will work 670-750 so you just have to decide what one you feel is right for your build. you would not overcarb the motor with a 750cfm. good luck with your choice.

 

[Meep-Meep]

I am not liking that cam for a stock rebuild - assuming you have stock compression. If you have tuning problems like I suspect you will then no carb will be happy until you change that cam to something more streetable. But to answer your question I'd stick to the smaller carb for the street.