Carb Questions 250 L6 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

culp7 · 02-22-2010, 10:57 PM

Right now i'm runnin a stock 250 and want to do a few performance upgrades.

List Right Now is:
Offy Intake
4-barrel carb
headers
MSD box.

My question is: Is a 500cfm Elderbrock to big to run on that application. I would run the Holley 390 but i'm just a huge elderbrock fan.

Thanks, Bryant

silverstreak · 02-23-2010, 12:04 AM

I've heard of a few people running the 500 on a six and were satisfied with it. I can understand your appreciation for the Edelbrock carb. I have one on my Ford 302 and love it. I would get a calibration kit for it and expect to tune it a bit, if you do go that route.
In all honesty though I think the 390 would have better manners on the street in regards to throttle response and gas mileage.

Brad · 02-23-2010, 01:38 AM

I ran the 500cfm for a number of years and loved it. I tried tuning it a bit but went right back to the stock jets and everything. All you'd have to do is set the idle speed, mixture and forget it!

psuautotechstudent · 02-23-2010, 02:50 AM

This is good info. I'm wanting to do the same or similar. Wonder how hard it would be to do a sequential EFI system on a 250. Let us know how 500 cfm works for you. Btw, What intake are you using?

culp7 · 02-23-2010, 11:12 AM

Quote:

Originally Posted by psuautotechstudent

This is good info. I'm wanting to do the same or similar. Wonder how hard it would be to do a sequential EFI system on a 250. Let us know how 500 cfm works for you. Btw, What intake are you using?

the offenhouser standard 4barrel ...eigther that or the clifford 4 barrel intake

but right now i'm runnin stock everything

culp7 · 02-23-2010, 09:38 PM

anyone else??

(bump)

**slomotion** · 02-27-2010, 12:09 AM

I'm running the Edelbrock 500 on my 292, and have had no problems at all right out of the box. It's on the Offy manifold with Langdon headers, and has proven to be an all-round great driver.
My personal preference is for the Edelbrock over Holley only because you can tune the Edelbrock on the engine, (the Holley has to come off, and I know we don't tune the carb every week end, "just sayin'") and the Edelbrock has no gaskets below the fuel level. JMHO

Shaky · 02-27-2010, 06:40 AM

I'm going back to a stock one-barrel on my sixes. I had a 250 with a Holley 390 on a Clifford intake, a hot cam, and headers. I was constantly messing with the Holley trying to get everything right.

I must be getting old - now I just want to cruise around without much fuss...

However, if I could find a port injection system (Clifford used to market one) I'd go with that...

PanelDeland · 02-27-2010, 06:47 AM

Spmeone on the site used a FI set up for a Jeep(IIRC) and was really pleased.I think it would be a performance and MPG upgrade.I don't think it would pay back very well just on fuel savings but if you wanted the performance also.If you can find a post on 6 cyl by either member Brad or Kyull,again IIRC,I believe the info and maybe a link was in that thread.

Here's a good thread on the 6.

http://67-72chevytrucks.com/vboard/s...d.php?t=276823

**slomotion** · 02-27-2010, 10:18 AM

Panel, thanks for that link! There's some outstanding I6's there!

I didn't take the time to research the dual-plane vs single-plane intakes shown in the images, but something I did notice throughout that thread was some square-bore 4bbl's were mounted fore and aft like they would be on a V8, and others bolted up at 90 deg with the primary's outboard.

I'm curious what the engine builders rationale is for each method. Any takers?

PanelDeland · 02-27-2010, 09:38 PM

It's usually a linkage thing.IIRC The earlier trucks with the mechanical linkage can be slighly modified to work while the cable systems will work the other way.This is as far as I remember.The adapters may also make a difference.Manifolds for the 6 are cast in one style with a flange that has an adapter bolted to it for whatever style.make carb you run.Member Full Foot Notch(Ithink) did a 3 dueces set-up on a 6 by having a custom adapter made.

**slomotion** · 02-27-2010, 10:26 PM

Sorry culp7, didn't mean to hijack your thread.

culp7 · 02-27-2010, 10:28 PM

Quote:

Originally Posted by slomotion

Sorry culp7, didn't mean to hijack your thread.

Don't worry bout it

02-22-2010, 10:57 PM	#1
culp7 HickTown Join Date: Apr 2009 Location: ANDOVER, Kansas Posts: 355	Carb Questions 250 L6 Right now i'm runnin a stock 250 and want to do a few performance upgrades. List Right Now is: Offy Intake 4-barrel carb headers MSD box. My question is: Is a 500cfm Elderbrock to big to run on that application. I would run the Holley 390 but i'm just a huge elderbrock fan. Thanks, Bryant __________________ 1993 Ford Mustang Vert w/ 2.3 1969 Chevy C/10 w/350 1968 Chevy C-20 w/250 1976 Dodge Aspen W/ 225 2000 Toyota Tundra w/4.7 1987 Dodge Ram D-100 w/360 255/70-15 ___________ (oo)══╬══(oo) ‾‾‾‾‾‾‾‾‾‾‾

02-23-2010, 12:04 AM	#2
silverstreak Registered User Join Date: Mar 2009 Location: USA Posts: 255	Re: Carb Questions 250 L6 I've heard of a few people running the 500 on a six and were satisfied with it. I can understand your appreciation for the Edelbrock carb. I have one on my Ford 302 and love it. I would get a calibration kit for it and expect to tune it a bit, if you do go that route. In all honesty though I think the 390 would have better manners on the street in regards to throttle response and gas mileage.

02-23-2010, 01:38 AM	#3
Brad Out of the carpool lane. Join Date: Jan 2000 Location: Clark Co, WA Posts: 5,672	Re: Carb Questions 250 L6 I ran the 500cfm for a number of years and loved it. I tried tuning it a bit but went right back to the stock jets and everything. All you'd have to do is set the idle speed, mixture and forget it! __________________ 1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten...

02-23-2010, 02:50 AM	#4
psuautotechstudent Registered User Join Date: Sep 2009 Location: Pittsburg, KS Posts: 39	Re: Carb Questions 250 L6 This is good info. I'm wanting to do the same or similar. Wonder how hard it would be to do a sequential EFI system on a 250. Let us know how 500 cfm works for you. Btw, What intake are you using? __________________ 1968 C10 250 I6

02-23-2010, 09:38 PM	#6
culp7 HickTown Join Date: Apr 2009 Location: ANDOVER, Kansas Posts: 355	Re: Carb Questions 250 L6 anyone else?? (bump) __________________ 1993 Ford Mustang Vert w/ 2.3 1969 Chevy C/10 w/350 1968 Chevy C-20 w/250 1976 Dodge Aspen W/ 225 2000 Toyota Tundra w/4.7 1987 Dodge Ram D-100 w/360 255/70-15 ___________ (oo)══╬══(oo) ‾‾‾‾‾‾‾‾‾‾‾ Last edited by culp7; 02-24-2010 at 10:59 AM.

02-27-2010, 12:09 AM	#7
slomotion Old Duffer Join Date: Mar 2003 Location: Maine Posts: 1,822	Re: Carb Questions 250 L6 I'm running the Edelbrock 500 on my 292, and have had no problems at all right out of the box. It's on the Offy manifold with Langdon headers, and has proven to be an all-round great driver. My personal preference is for the Edelbrock over Holley only because you can tune the Edelbrock on the engine, (the Holley has to come off, and I know we don't tune the carb every week end, "just sayin'") and the Edelbrock has no gaskets below the fuel level. JMHO __________________ '68 Short C20 Flatbed Dually w/ 292 4bbl, Langdon cast headers, and WC T5 trans. '81 G10 Shorty Van "Good judgement comes from experience, and a lot of that comes from bad judgement." Will Rogers "Under promise, then over achieve."

02-27-2010, 06:40 AM	#8
Shaky Six in a row makes it go... Join Date: Mar 2009 Location: Vacationland: Maine Posts: 1,346	Re: Carb Questions 250 L6 I'm going back to a stock one-barrel on my sixes. I had a 250 with a Holley 390 on a Clifford intake, a hot cam, and headers. I was constantly messing with the Holley trying to get everything right. I must be getting old - now I just want to cruise around without much fuss... However, if I could find a port injection system (Clifford used to market one) I'd go with that... __________________ 67 C20 long step resto: http://67-72chevytrucks.com/vboard/s...d.php?t=342086 66 C10 long step build: http://67-72chevytrucks.com/vboard/s...=1#post3814790 CT to Alaska in a 67 C10: http://67-72chevytrucks.com/vboard/s...d.php?t=399224 “The height of sophistication is simplicity." - Clare Boothe Luce Last edited by Shaky; 02-27-2010 at 06:43 AM.

02-27-2010, 06:47 AM	#9
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: Carb Questions 250 L6 Spmeone on the site used a FI set up for a Jeep(IIRC) and was really pleased.I think it would be a performance and MPG upgrade.I don't think it would pay back very well just on fuel savings but if you wanted the performance also.If you can find a post on 6 cyl by either member Brad or Kyull,again IIRC,I believe the info and maybe a link was in that thread. Here's a good thread on the 6. http://67-72chevytrucks.com/vboard/s...d.php?t=276823 __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil" Last edited by PanelDeland; 02-27-2010 at 06:55 AM.

02-27-2010, 10:18 AM	#10
slomotion Old Duffer Join Date: Mar 2003 Location: Maine Posts: 1,822	Re: Carb Questions 250 L6 Panel, thanks for that link! There's some outstanding I6's there! I didn't take the time to research the dual-plane vs single-plane intakes shown in the images, but something I did notice throughout that thread was some square-bore 4bbl's were mounted fore and aft like they would be on a V8, and others bolted up at 90 deg with the primary's outboard. I'm curious what the engine builders rationale is for each method. Any takers? __________________ '68 Short C20 Flatbed Dually w/ 292 4bbl, Langdon cast headers, and WC T5 trans. '81 G10 Shorty Van "Good judgement comes from experience, and a lot of that comes from bad judgement." Will Rogers "Under promise, then over achieve."

02-27-2010, 09:38 PM	#11
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: Carb Questions 250 L6 It's usually a linkage thing.IIRC The earlier trucks with the mechanical linkage can be slighly modified to work while the cable systems will work the other way.This is as far as I remember.The adapters may also make a difference.Manifolds for the 6 are cast in one style with a flange that has an adapter bolted to it for whatever style.make carb you run.Member Full Foot Notch(Ithink) did a 3 dueces set-up on a 6 by having a custom adapter made. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

02-27-2010, 10:26 PM	#12
slomotion Old Duffer Join Date: Mar 2003 Location: Maine Posts: 1,822	Re: Carb Questions 250 L6 Sorry culp7, didn't mean to hijack your thread. __________________ '68 Short C20 Flatbed Dually w/ 292 4bbl, Langdon cast headers, and WC T5 trans. '81 G10 Shorty Van "Good judgement comes from experience, and a lot of that comes from bad judgement." Will Rogers "Under promise, then over achieve."

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