CFM of quadrajet
 

Any one know the cfm of the stock carb on the 91 502 mag. motor.How much horse power will this carb support?

Re: CFM of quadrajet
 

750cfm
I've been told if you find the right guy to tune it, 425-450hp

Re: CFM of quadrajet
 

Payton is correct. They can be a very good carb.

Re: CFM of quadrajet
 

I thought it was 850 cfm while the SBC's ran a 750 cfm??

Re: CFM of quadrajet
 

I was told from way back from the folks at Jomar Engineering in the Detroit area that "Rochester carbs only come in TWO (2) different CFM sizes; 780cfm and 800cfm---period!" -----But I am not going to stake my life on what I was told so, take the info I have just given as you may.

Re: CFM of quadrajet
 

But the real question that i've asked a hundred times is, how do you identify what size the carb is, based on looking at it?

I have a 1991 boat with a 502 mag. When i run the s/n of the motor by mercruiser they say it's an MPI motor, a '94. But it's carbed now, and i don't know what size the carb is.

What's the number on top of the carb on you're 91 502, nordic95?

Re: CFM of quadrajet
 

I dont have them right now.They are at the engine shop.I was just wondering if I could get them to support 500 to 550 horse.I spent a lot of time at the drap strip years ago and some of those guys were running 650 hp and more on 850 cfm quadrajets.

Re: CFM of quadrajet
 

1-3/32 in venturi (primary) 750 CFM
1-7/32 in venturi (primary) 800 CFM

Re: CFM of quadrajet
 

So if I have the 800 cfm ,how much horse power can this support?