6 Cylinder Carburation

[blazerparts]

Just wondering what you I6 guys do for carbs. I am thinking of replacing the monojet with something else, perhaps a holly 2 bbl, 350 or 500 cfm?

[shifty]

when i had mine in the truck, i as using the stock 1bbl. the thing was enough of a gas hog as it was. i went with aftermarket headers on the stock intake. i believe if you're moving to a 2bbl, you'll need to either get the offenshauser or clifford intake which supports a 4bbl carb ... you can get a 4bbl to 2bbl adapter to use that 2bbl with it. the clifford is nice and you can find it for sale almost anywhere including JC Whitney.

[68Stepbed]

Honest Charley's in Chattanooga, TN sells adapters to fit Stromberg 97's and Rochester 2GC carbs. You can pick up to 50 hp just swapping to a Stromberg.

[blazerparts]

Originally Posted by 68Stepbed

Honest Charley's in Chattanooga, TN sells adapters to fit Stromberg 97's and Rochester 2GC carbs. You can pick up to 50 hp just swapping to a Stromberg.

Summit doesn't stock Stromberg carbs.......where do I find this animal and does Honest Charley's have a website? Thanks for the info.

[Brad]

I've got a Weber 32/36 on mine with a Clifford adaptor. It works ok, but I'm sure it would run better if I had it tuned and adjusted. Down the road I'll be putting on my 4bbl on a Clifford manifold.

[ChevyMex]

What is the benefit going from a monojet carb to a 2bbl or 4bbl in a inline six cylinder?

[cdowns]

stromberg 97's are really a pain to run they almost always leak and need constant upkeep, they're available on ebay all the time for around $200 each for a core(some needing $200-$300 rebuilds) if you want to go old school type of carb the one to use is the holley 94 it's a far more reliable carb set it up and it's good for 20years the added bonus is they atomise the fuel better and flow more than stock 97's will. i've only got a dozen or so left so i'm not selling any of mine// you can get a 2X2 adapter to bolt onto a 4barrell manifold if you need a cool lookin intake system// but if you want best reliable you'd be better off with the 4brl intace and the 390holley 4brl

b-4 and after holley 94's

['68OrangeSunshine]

After a rebuild in '77 of a 292 L6 at .030 over, [on a '68 C/10 Stepside] I first tried to use a Holley-Weber 2 Bbl from a Vega. Although I got an adapter to mount it on the stock manifold, I was told it would not have enough CFM. So I went with the Holley 4160 type R-8007 w/ 390 CFM, on an Offenhauser 4Bbl intake and Clifford Research headers. I got about 250,000 miles out of this configuration, but by 2002 the old L6 was dragging. So I rebuilt the original 292 block which I had saved. By Jan of 2005 the new rebuild was done and
I had a Holley expert buddy remake the 390. The Offy intake was glass beaded by my machinist and came up nice, the Clifford "Viper" headers were hot tanked and media-blasted and only required a couple of coats of VHT Hi Temp cast iron gray. The Holley self-destructed after some early teething problems with manifold leaks and I decided to go with a Carter AFB type. AFBs are now made by Edelbrock as the "Performer Series" Also Edelbrock doesn't make a 400 CFM model (like Carter did) so I had to go with a 500 CFM EDL-1404. We had to play with springs and metering rods, to get it all lined out, but the result is some hi-torque, seat-of- the -pants fun.
Gas mileage isn't any worse than the old engine ~12.5 MPG.

[blazerparts]

Originally Posted by '68OrangeSunshine

After a rebuild in '77 of a 292 L6 at .030 over, [on a '68 C/10 Stepside] I first tried to use a Holley-Weber 2 Bbl from a Vega. Although I got an adapter to mount it on the stock manifold, I was told it would not have enough CFM. So I went with the Holley 4160 type R-8007 w/ 390 CFM, on an Offenhauser 4Bbl intake and Clifford Research headers. I got about 250,000 miles out of this configuration, but by 2002 the old L6 was dragging. So I rebuilt the original 292 block which I had saved. By Jan of 2005 the new rebuild was done and
I had a Holley expert buddy remake the 390. The Offy intake was glass beaded by my machinist and came up nice, the Clifford "Viper" headers were hot tanked and media-blasted and only required a couple of coats of VHT Hi Temp cast iron gray. The Holley self-destructed after some early teething problems with manifold leaks and I decided to go with a Carter AFB type. AFBs are now made by Edelbrock as the "Performer Series" Also Edelbrock doesn't make a 400 CFM model (like Carter did) so I had to go with a 500 CFM EDL-1404. We had to play with springs and metering rods, to get it all lined out, but the result is some hi-torque, seat-of- the -pants fun.
Gas mileage isn't any worse than the old engine ~12.5 MPG.

Sounds like what I'm after, where are the intake and header available?

[jimfulco]

I used a Carter 2-bbl with an adapter on a '69 Nova 230 way back yonder. It seemed to add a little horsepower, but only enough to barely notice, nowhere near 50hp. It had stock exhaust, so maybe that limited it somewhat.

['68OrangeSunshine]

Originally Posted by blazerparts

Sounds like what I'm after, where are the intake and header available?

Best sources for Hi Perf L6 parts:
Tom Langdon's www.stoveboltengineco.com
or Clifford: www.cliffordperformance.net
Even J.C. Whitney has the 390 Holley and the Offy 4Bbl intake (but a little spendy) www.jcwhitney.com
Clifford headers are available from Clifford directly, or you might shop around. I got mine at a local speed shop, back in the day. (But they don't cost $79 bucks anymore!)
Clifford doesn't sell the Offy intake, obviously. Their 4Bbl intake is a good product, but in my opinion it's engineered for the drag racer and hot street rodder -- it runs better at higher RPMs. The Offy intake is reputed to be better at low RPM/ high torque operation. Such as you would use on a truck.
Tom Langdon is a retired GM design/test engineer. He KNOWS the L-22 ["Late" L6s] from professional experience. Also a nice guy. He helped me find a set of 292 pushrods when I couldn't get 'em for love or money anywhere else for only $40 bucks. And helped me out with tech advice by email when the new 292 project was teething.
If you hadn't heard about it before, the Bible on hot L6s is Leo Santucci's
"Chevrolet Inline Six-Cylinder Power Manual" published by California Bill's Automotive Handbooks, Tucson, AZ, (c.)2002. You can get one from the Inliners International,www.inliners.org
They [WE] have a great site and don't mind sharing sixbanger info.
Hope this helps.

[Fred T]

Best milage and performance I ever got out of a stock Chevy six was an 80 van. It had the 250 with a progressive 2 bbl rochester. 19 mpg. And a lot more power than a one bbl. Iirc, it was a half of a q-jet. Problem came from pot metal wear. Rebuild was around $180 in 1986.

If you want a bolt-on package, go with the Holley 390 4 bbl. If you want performance and milage and can do some metal work, got with Langdon's 2 bbl holley-weber, a pair of them. Get a dual one bbl intake, cut off the one bbl. mounts and weld on some 2 bbl mounts. Langdons adapters work, but they don't look that great.

[blazerparts]

Great......thanks for the info all.

[speedracer]

390 holley is a great carb!!

[69_hafton]

I've been wondering if anyone is using a weber 32/36 (progressive - 2bbl) - these are pretty common, but would have to redo the jets for the bigger engine. Maybe it's too small of a carb, but I've seen kits for sale with the weber 38/38 (from clifford and others, I think), but this wouldn't be good on gas as the 32/36