Would a 750cfm work fine with my motor? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TIMSPEED · 03-29-2004, 12:48 AM

I'm thinking about ditching my little Holley 600 and either getting an Edelbrock 750 or a Jet Quadrajet. My only question is, how well with the 750 work with my MILD 355? I'm planning on swapping to a Vortec/XE274/RPM Air Gap soon, but for now, my MILD 355 will have to do.

*1FaastC10* · 03-29-2004, 12:55 AM

Jet it, 750 holley is WAY too big for your 350 unless you've got the potential of running gobs of horsepower. your 350 crate isnt anywhere near "gobs"

kevhill85 · 03-29-2004, 01:00 AM

i run the xe268 and the 750(holley ) had to be jeted up more .

*1FaastC10* · 03-29-2004, 01:31 AM

there's a formula out there somewhere to figure out how many CFM an engine should require, and 750 cfm falls somewhere around 8000 rpms on a 350. 600 is actually a little bit big for a daily driver 350. plus, the smaller cfm will give you better throttle response and torque.

ocbaud · 03-29-2004, 02:10 AM

my engine needs about 667cfm at 100%ve.

jimfulco · 03-29-2004, 02:28 AM

A Q-jet will only flow 750cfm if the motor asks it to. Otherwise the secondary air valves just won't open all the way. They used them on in-line sixes 35 years ago. The smaller primaries & extra boosters make for excellent driveability & mileage. Problem is, Edelbrock told me recently that they have no plans for an RPM Q-jet intake for Vortec heads

, so sooner or later you'll be needing a square-bore carb anyway.

Tom · 03-29-2004, 03:10 AM

To answer your question: Yes it will work fine. I ran a 750 carter on my stock vortec 350 for a while, made better power and low end torque then the 600 I replaced it with. Figure that out with your math forumlas :p

boraxman · 03-29-2004, 05:44 PM

Check the Holley 670 Street Avenger. They have vacume secondaries and are rated for 300-400hp engines. I have one and it works great.

Theres a guy that sells lots of them on Ebay. Can be had for $200 or less.

03-29-2004, 12:48 AM	#1
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Would a 750cfm work fine with my motor? I'm thinking about ditching my little Holley 600 and either getting an Edelbrock 750 or a Jet Quadrajet. My only question is, how well with the 750 work with my MILD 355? I'm planning on swapping to a Vortec/XE274/RPM Air Gap soon, but for now, my MILD 355 will have to do. __________________ I have a few cars... See Them Here

03-29-2004, 01:00 AM	#3
kevhill85 91 SWB 383 Join Date: Feb 2003 Location: Crandall,TX Posts: 643	i run the xe268 and the 750(holley ) had to be jeted up more . __________________ 96 2dr Tahoe protruning LS1 347/4L60L, PSI harness, body dropped, 4link, 6lug conv, narrowed rearend, Schoenfeld headers, 2600 stall, 317 heads milled .040, http://photobucket.com/albums/q169/k...ahoe prostreet

03-29-2004, 03:10 AM	#7
Tom driving is in my blood Join Date: Dec 1999 Location: Mesa AZ Posts: 5,713	To answer your question: Yes it will work fine. I ran a 750 carter on my stock vortec 350 for a while, made better power and low end torque then the 600 I replaced it with. Figure that out with your math forumlas :p __________________ -78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me.

03-29-2004, 05:44 PM	#8
boraxman Keepin an eye out Join Date: Feb 2003 Location: So.Cal Posts: 3,921	Check the Holley 670 Street Avenger. They have vacume secondaries and are rated for 300-400hp engines. I have one and it works great. Theres a guy that sells lots of them on Ebay. Can be had for $200 or less. __________________ 1970 Chevy C10 SWB 5.3 1996 Toyota Tacoma SR5 4x4 2007 Vespa GTS 250 Scooter ZIP 91351

03-29-2004, 12:55 AM	#2
1FaastC10 Account Suspended Join Date: Oct 2002 Location: Elkhart, IN Posts: 6,400	Jet it, 750 holley is WAY too big for your 350 unless you've got the potential of running gobs of horsepower. your 350 crate isnt anywhere near "gobs"

03-29-2004, 01:31 AM	#4
1FaastC10 Account Suspended Join Date: Oct 2002 Location: Elkhart, IN Posts: 6,400	there's a formula out there somewhere to figure out how many CFM an engine should require, and 750 cfm falls somewhere around 8000 rpms on a 350. 600 is actually a little bit big for a daily driver 350. plus, the smaller cfm will give you better throttle response and torque.

03-29-2004, 02:10 AM	#5
ocbaud Garage Queen Material Join Date: Oct 2002 Location: USA Posts: 4,129	my engine needs about 667cfm at 100%ve.

03-29-2004, 02:28 AM	#6
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	A Q-jet will only flow 750cfm if the motor asks it to. Otherwise the secondary air valves just won't open all the way. They used them on in-line sixes 35 years ago. The smaller primaries & extra boosters make for excellent driveability & mileage. Problem is, Edelbrock told me recently that they have no plans for an RPM Q-jet intake for Vortec heads , so sooner or later you'll be needing a square-bore carb anyway.



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