Surfing around the intertubes during some downtime at work last night, I came across a dual carb Offy intake for single barrel carbs. Has anyone here had any experience with it? I think it's kind of cool, but I honestly doubt I'd sink $400+ for it when the engine I'm getting already has a complete Super Six setup.

Just seemed kinda need to me though:

_________________
'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Many have run these and they can be cheaper than your quote ( I think $250.00 will get one).


They suppose to work good if you have two good carbs. I bet they have better cylinder distribution than any of the other intakes and I have been wanting to try one. I would run phenolic spacers under the carbs so heat problems boiling the gas would not be a problem which I have heard will happen to the rear carb after a heat soak ( going into a store and coming out to restart).



Jess

Yeah I just saw one on Summit for just under $300. I have to admit, it looks like a good way to get better mixture distribution to the cylinders, like you mentioned. Good idea on the phenolic spacers. I just might have to give this a try if I can find a couple good (rebuilable) Carter BBS units and have the leftover cash in my budget once all my other priorities are taken care of.

Though before doing this I'd rather sink the cash into a set of Dutra Duals, then a pair of fuel ratio gauges so I could keep both carbs tuned correctly if I get that intake...

_________________
'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

H'mm. Haven't heard of any particular heat-soak issues with the twin 1bbl intake, rear-carb-specific or otherwise. I don't think special phenolic spacers would be necessary, and I'm not sure they'd even be desireable; I'd just use the regular 3/8" thick insulating carb base gaskets. This manifold's design is actually less prone to percolate the carbs than the factory central-carb setup. This intake was released in 1961, and the linkage it comes with is meant for use with the '60-'66 A-bodies with rotating-rod throttle/kickdown linkage. You're on your own (custom fabrication) if you want to use this intake with a cable-operated throttle control as found on '62-up big cars, '65-up A-bodies with factory air, and all '67-up A-bodies. The key to making this manifold work is matched carburetors. Matched in type number, condition, and calibration. Not just two similar slant-6 one-barrel carbs, but two new Carter BBS 4692A carbs (just pulling that number out of the air, for illustration). Choke info for this manifold is here. There've been some very clean installations of this intake by members here on the board. A '63 Dart comes to mind, but I can't recall whose!

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Those intakes work very well with 2 BBD's on them too. The carb mounting flanges are big enough that you can drill the holes for the mounting studs and cut out the center.

_________________
Official Cookie and Mater Tormentor.

The Pro-Line set-up was based on this manifold.
The carb mounting pads does allow for larger carb mounting if you want to go with something besides the SL6 1 bbl units.
DD

You reinforced what I assumed, about needing two identical carbs for it to work correctly. I've heard of a guy in Lynwood, WA (right near where my folks live actually) who does good carb work, so I'm going to go to him while I'm home and see about the cost of two identical Carter BBS's while getting a BBD for the Super Six currently on the '66 engine I'll be getting. Interesting that heat soak shouldn't be an issue. I figured it would be, but it'd be worth trying as-is before spending the money for phenolic spacers (not that they'd cost me anything since I can get most of the materials I'd ever need from our maintenence shops, including any machine/CNC work).
I wonder how difficult it'd be to adapt a cable throttle control for use with this manifold, since my '74 uses a cable (obviously)...

_________________
'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

For accelerator linkage fabrication ideas, you may want to look at this thread. It would be a lot easier to put together a cable bracket that would operate a pair of 2bbl carbs with perpendicular mounting (throttle lever moves fore-and-aft) than to put together a setup to operate a pair of 1bbbl carbs with parallel mounting. You may want to explore all your carb options including the progressive Weber types and suchlike.

Auto trans kickdown is no big deal; use the Bouchillon kickdown cable kit which employs mostly late-model factory parts.

Heat soak should be reduced for a couple of reasons: This intake does have exhaust heating via a well-thought-out pair of hoop-shaped passages cast into the underside of the intake, but no carb is mounted directly above the intake-to-exhaust manifold junction. And, with two carbs side by side, there's generally not a lot of room for great big air cleaners that would tend to trap heat under them! Usually people wind up using two small air cleaners. The '63-'67 "small and tall" 1bbl air cleaners will fit side by each, though if you use something other than stock-type 1bbl carbs, the base plates will have to be modified or adapted. I wish I had the metalwork skills and facilities to be able to create an oblong air cleaner assembly like the factory triple-2bbl "six pack" setups used. it would take a lot of careful measuring and artful welding. The other option, good for clearance with the hood and A/C if present, would be to put on a couple of carb "hats" and run ductwork to a remote air cleaner.

If you investigate matched BBSs, see if your guy in Lynwood can supply some later-model units, such as 4955 or 4956 ('71 198, manual/auto trans). The later BBSs have multi-stage step-up systems and other advancements and tweaks that improve fuel metering accuracy.

Or, come to think of it, you could use a pair of Holley 1945s. New ones are relatively easy to come by, they all have self-contained throttle return springs and are calibrated for precise control over fuel metering at low airflow (which becomes more important when you halve the airflow through each carb by doubling the carb count).

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

I can't claim very clean, but here's an example:





I had some trouble with hood clearance, so that's why I have the open element base on the front carb, it sits a little bit lower than the 9" closed element air cleaner, even with the dropped base air cleaner piece shown.

Works well for me, the only issue I had was getting the spring tensions correct with the kit--it required some extra engineering and if I did it again, I would replace a lot of the adjustable rods with heim joints so that it wouldn't slip around on me.

MJ

Heim joints...? Not familiar with 'em...

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks Ross, that's what I was talking about. I'd like to replace those long sliders that simply attach with a pinch fit from an allen bolt. My spring tensions weren't quite right, and one time I came to a stop and the bolt stopped holding, and the accelerator stuck down. Unfortunately I was at a 4 way stop and started lighting up the rear tires before I could shut it off. At the corner, of course, was your local neighborhood cop in the posh little town I was in (Menlo Park, CA for those of you familiar with the Bay Area).

He came over to investigate, but the moment I popped the hood he stopped hassling me and just started chatting cars. He was a Chevy guy, but hey, no ticket for reckless driving, so I was happy =)

They've been used for the last few years on aftermarket six pack and dual quad installations to make things a bit less 'sloppy'... the instalations in those cases look good (very clean), the linkage is tighter, but I haven't followed how people like that style over the OEM install.

-D.Idiot

I've got one of these manifolds and think it might be trick with a pair of throttle body injection units. Better fuel distribution than a 2bbl manifold and throttle body, but less work than port EFI.

Megasquirt can handle the fuel for nitrous enrichment so I hope 2 K-car throttle body injectors will flow enough fuel for say 75 more horsepower.

_________________
Joshua

the only heat issues I've had running this setup with twin 1 barrels is that the rear half of that manifold gets a little hotter due to fan cooling the front half. I used to run a 58 jet in the front and a 60 jet in the back and that solved the issue.

_________________
Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.