Home page
  Home Page   Contact Us   Our History   Advertise with Us   Sponsor List   Link to Us   Compare Levels   Member Agreement   Privacy Policy   About C3VR
  Community Forums   Active Threads   Forum Search   Top Posters List   Private Messenger   C3VR Email System   C3 Corvette Quiz
  Members Vettes & Pictures   Member Stories   Member Stats   Real Time Member Map   Member Search   Lifetime Member List   Member Calendar Entry Form   Who's Online
  C3 Registry Data   C3 Corvette Statistics   C3 Corvette Tips & Tricks   C3 Corvette How-Tos   Corvette Club Listing   Corvette Event Listing   Mechanic Directory   Corvette VIN Decoder   Save the Wave   Corvette Emblem History   C3 Corvette Birthday Calculator   C3 Corvette Build Dates   Corvette Parts Illustration Catalog   Shark Bytes - Online
  C3 Corvette Parts Auctions on eBay   Corvette Books   C3VR In-Stock Apparel & Accessories   C3VR Member Name Badges   C3VR Custom Apparel & Accessories @ Zazzle   C3VR Window Stickers   C3VR Member Deals & Discounts   C3VR Member Calendars   Shop Amazon.com
☰
SPONSOR AD

Topic: Carb CFM rating for 454

in Forum: C3 Fuel, Emission Control, and Exhaust Systems

Already a Member? Click Here to Login

Carb CFM rating for 454

Posted: 5/23/07 10:09am Message 1 of 6
windrider1200
Gold MemberGold Member
Send PM
Clifton, NJ - USA
Joined: 10/3/2003
Posts: 129
Vette(s): 1972 Coupe Ontario Orange Black leather interior LS-5; Turbo 400
I'm about to dive into fine tuning the carb on my mildly moded 72 454 with a LM-1 Wideband O2 AFM setup. A couple of local sages have opinioned that the Holley Squarebore  600 CFM carb might be too small for the engine.  As we discussed it, they focused on how much the throttleplates would need to be opened at idle to flow the air required, and they thought that too much of the transition slots would need to be exposed.
 
Any thoughts??
 
BB NJ Ken



1972 T Top 454; "Boomer" Latest "upgrades": 1 1/8" front Stabilizer bar. Rebuilt SS calipers with O-ring pistons. Under car Chambered exhaust. Fiberglass rear spring (360lbs/in). Bilstein Rear Shocks. 3/4" Rear Stabilizer Bar. Tow hitch. Performer manifold with 600 cfm Holley. Comp Cam 262 .499 lift. L-88 Hood in process

SPONSOR AD:: (Our Sponsors help support C3VR)

Carb CFM rating for 454

Posted: 5/23/07 12:37pm Message 2 of 6
knotacare
Limited Member
Send PM
Newark, DE - USA
Joined: 7/26/2004
Posts: 468
Vette(s): 1968 Conv, 454HO,500HP-600TQ, TKO-600,3:70 HD rear,hotrod air, custom paint & suspension,1973 Ruby Red,T-top, 383 Stroker, TK)-500,frame off restro, 1967 Dodge Coronet, 340 stroker to 406, Dana 60
I have a 750 on mine & that's probasbly what you need. 600 is to small
Alan



                                               

Carb CFM rating for 454

Posted: 5/23/07 1:12pm Message 3 of 6
Profile Pic
Gunslinger
Former Member
Send PM
Frederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
I agree...750-800 cfm is what you need or you'll run out of steam pretty quickly.

I'm not knocking Holley but I prefer Edelbrock or Demon carbs.

If money isn't a major obstacle...two words...fuel injection!


Carb CFM rating for 454

Posted: 5/23/07 2:41pm Message 4 of 6
knotacare
Limited Member
Send PM
Newark, DE - USA
Joined: 7/26/2004
Posts: 468
Vette(s): 1968 Conv, 454HO,500HP-600TQ, TKO-600,3:70 HD rear,hotrod air, custom paint & suspension,1973 Ruby Red,T-top, 383 Stroker, TK)-500,frame off restro, 1967 Dodge Coronet, 340 stroker to 406, Dana 60
I also agree the Edelbrock being a better driver carb & the speed demon gives more top end power, but worse gas mileage. The demon looks like a monster next to the Edelbrock. I use both on mine just switch them depending on the mod I'm in..
Alan



                                               

Carb CFM rating for 454

Posted: 5/23/07 7:08pm Message 5 of 6
windrider1200
Gold MemberGold Member
Send PM
Clifton, NJ - USA
Joined: 10/3/2003
Posts: 129
Vette(s): 1972 Coupe Ontario Orange Black leather interior LS-5; Turbo 400
Thanks all for the inputs. If I wasn't on the verge of moving, I'd go fuel injection, but now that is at least a year away.

I put the 600 cfm on go real good low speed throttle reponse, the cam is a .500 lift, short duration, bottom end torque bump stick.

I happen to have a 780 cfm Vac secondary carb in stock, but I thought the smaller throttle plates in the 600 cfm would give the best low speed to 5000. My ride, like myself, is built for comfort, not for speed.

Anyway, I'll give the 600 a shot, and see what happens, If I'm not impressed, I'll go with the 780.

Thanks again;

BB NJ Ken



1972 T Top 454; "Boomer" Latest "upgrades": 1 1/8" front Stabilizer bar. Rebuilt SS calipers with O-ring pistons. Under car Chambered exhaust. Fiberglass rear spring (360lbs/in). Bilstein Rear Shocks. 3/4" Rear Stabilizer Bar. Tow hitch. Performer manifold with 600 cfm Holley. Comp Cam 262 .499 lift. L-88 Hood in process

Carb CFM rating for 454

Posted: 5/23/07 7:51pm Message 6 of 6
Profile Pic
Adams' Apple
Lifetime MemberLifetime Member
Moderator
Send PM
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
The size of the primary throttle blades really shouldn't effect the idle, even if you're running a monster duration cam, which you say it's not("short duration"). If you have a long duration/overlap cam, then you can always poke(drill) a couple of small holes in the throttle blades as idle air bleeds....this keeps the throttle blades closed, and the transition slots covered at idle.
That being said...I'd have to agree that the 600 is simply too small, even for a stock b-block.


Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

in Forum: C3 Fuel, Emission Control, and Exhaust Systems


SPONSOR AD: (Our Sponsors help support C3VR)