Carb CFM help...HELP!!!

Shawn · 11-11-1999, 08:01 PM

I have a 351c in my car with stage II ported-2v heads, stage II ported Performer RPM manifold, 10.5:1 compression, hyd tappet cam .543" 305deg 110 lobe seperation, 1 7/8" headers and a 600cfm Carter-mechanical sec's polished to 630cfm.
I'm running mid 13's in my 1981 Fairmont with a somewhat poor C4 auto...

I've been thinking that I need to jump upto a bigger carb since I recently had my heads and manifold ported, I'm looking for recomendations anything will help as I only know EFI. I've been thinking 750cfm would be a good number knowing that a friend had I had went from 650 to 850 and lost power...what do you think??

THANKS!!!!

Ron1 · 11-12-1999, 12:15 PM

My mechanic would have a fit, if he saw the size of your carb. I run a 750 Demon on my 306, and an Edelbrock 750 on one I just sold. With the porting you have done a 750 should be no problem, and pick up some HP at the same time. If you do decide on something like a Demon, call them and tell them your set-up, and get a prelim. jet sizing and cam spec. I would suggest some Dyno time, to get it really dialed in.

Ron

RichLich · 11-15-1999, 10:56 AM

Ron1,

I'm not a carb expert, but the guys at Performance Auto Warehouse or Summit Racing probably have some good advice. I suspect there is either a Holley or Edelbrock carb that will work better for you.

Rich

PKRWUD · 11-18-1999, 08:07 PM

Get yourself a Holley #4779. It's a 750 double pumper. It will only bring smiles to your face.

Take care,
-Chris

------------------
Moderator at:
MustangNet

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!
'64 Falcon/Ranchero: 302+.040, 10.5:1, .475", 282 Dur., Perf. RPM, Holley 750 Dbl Pumper, MSD, 4-Spd., 8.8 w/3.73 posi. = 12.888 @109 MPH

Ron1 · 11-19-1999, 12:31 AM

Well, I went from a Holley Double Pumper to the Barry Grant Demon, we picked up roughly 40 HP at the rear wheels. We were only able to make a limited number of passes (last day of the season), and had poor track conditions, but my best went from a 10.70 to a 10.52. We also went flat at the top end of the track, so I am going to a Barry Grant BG280 to keep up with the extra fuel demands. Also increasing line size from 8an between the cell and pump to 10an. Should have all the new parts in by mid December, and will re-dyno then.

Ron

PS..I was smiling!!!!!

[This message has been edited by Ron1 (edited 11-19-1999).]

MEDIK418 · 11-20-1999, 07:52 PM

These guys are right Shawn. I have a cleveland similar to yours with a Holley 4160. It runs ok and as long as my 16 year old is driving it it'll stay that way but if you want to make some major power improvement go to at least a 750. Stock Clevelands will even digest an 800 with no problem and it will really wake the engine up in the upper rev range.

11-11-1999, 08:01 PM	#1
Shawn Registered Member Join Date: Dec 1998 Location: Chicago, IL. USA Posts: 77	Carb CFM help...HELP!!! I have a 351c in my car with stage II ported-2v heads, stage II ported Performer RPM manifold, 10.5:1 compression, hyd tappet cam .543" 305deg 110 lobe seperation, 1 7/8" headers and a 600cfm Carter-mechanical sec's polished to 630cfm. I'm running mid 13's in my 1981 Fairmont with a somewhat poor C4 auto... I've been thinking that I need to jump upto a bigger carb since I recently had my heads and manifold ported, I'm looking for recomendations anything will help as I only know EFI. I've been thinking 750cfm would be a good number knowing that a friend had I had went from 650 to 850 and lost power...what do you think?? THANKS!!!!

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11-12-1999, 12:15 PM	#2
Ron1 Registered Member Join Date: Sep 1999 Location: Vancouver, WA USA Posts: 439	My mechanic would have a fit, if he saw the size of your carb. I run a 750 Demon on my 306, and an Edelbrock 750 on one I just sold. With the porting you have done a 750 should be no problem, and pick up some HP at the same time. If you do decide on something like a Demon, call them and tell them your set-up, and get a prelim. jet sizing and cam spec. I would suggest some Dyno time, to get it really dialed in. Ron

11-15-1999, 10:56 AM	#3
RichLich Registered Member Join Date: Jul 1999 Location: Sterling, VA, USA Posts: 4	Ron1, I'm not a carb expert, but the guys at Performance Auto Warehouse or Summit Racing probably have some good advice. I suspect there is either a Holley or Edelbrock carb that will work better for you. Rich

11-18-1999, 08:07 PM	#4
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Get yourself a Holley #4779. It's a 750 double pumper. It will only bring smiles to your face. Take care, -Chris ------------------ Moderator at: MustangNet RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!! '64 Falcon/Ranchero: 302+.040, 10.5:1, .475", 282 Dur., Perf. RPM, Holley 750 Dbl Pumper, MSD, 4-Spd., 8.8 w/3.73 posi. = 12.888 @109 MPH

11-19-1999, 12:31 AM	#5
Ron1 Registered Member Join Date: Sep 1999 Location: Vancouver, WA USA Posts: 439	Well, I went from a Holley Double Pumper to the Barry Grant Demon, we picked up roughly 40 HP at the rear wheels. We were only able to make a limited number of passes (last day of the season), and had poor track conditions, but my best went from a 10.70 to a 10.52. We also went flat at the top end of the track, so I am going to a Barry Grant BG280 to keep up with the extra fuel demands. Also increasing line size from 8an between the cell and pump to 10an. Should have all the new parts in by mid December, and will re-dyno then. Ron PS..I was smiling!!!!! [This message has been edited by Ron1 (edited 11-19-1999).]

11-20-1999, 07:52 PM	#6
MEDIK418 Registered Member Join Date: Mar 1999 Location: Amarillo, Texas, USA Posts: 780	These guys are right Shawn. I have a cleveland similar to yours with a Holley 4160. It runs ok and as long as my 16 year old is driving it it'll stay that way but if you want to make some major power improvement go to at least a 750. Stock Clevelands will even digest an 800 with no problem and it will really wake the engine up in the upper rev range.