71 198 slant 3 on tree

Johnny71dusty

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I’m looking for the adapter to put up two barrel carburetor on this car ? I found them easy 15 years ago on my other darts I had . Now I can’t find anything .

I know people think it’s dumb , I don’t care I like my single barrels just fine but upping to a small 2bbl does help a bit and will allow me to do the smallest 2bbl efi on it
 

AJ/FormS

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Is this project for fuel-economy purposes? What are you hoping to gain, and what is the projected pay-back period?
I did a similar thing.
By gearing your engine down with overdrive, the cruise rpm would get so low, that IMO a Single-bbl cannot atomize properly. The smaller venturies of the 2bbl solved that for me, and the fuel economy on the hi-way went up.
However;
1) if you are switching to port-EFI, this is of no benefit because the carb becomes just an air valve, so you can install a "carb" with any size butterflies or venturies. However, for driveability, you need to use good judgement, because with a 1:1 ratio, she gets jumpy with a pair of too big valves, and after a point, the fuel curve would go very lean.
2) if installing TBI-injection on the SS 2bbl with the injectors above the valves, well IDK; I suppose it would depend on the size of the injector(s) cuz I suspect there would be very little room for air to get around them. Plus, TBI on this application, (stock 198slanty/ non-overdrive), for fuel-economy,
IMO, to put it kindly; Is a waste of time and resources.
But, with the injectors below the valves, IDK either, but it would be better than above, and probably easier. But again;
even with 2.76 gears and 65=2500rpm, that EFI will be very little better than a well-tuned carb........
Until you get the cruise-rpm down to sub-2000, where it becomes impossible for the stock distributor to supply the correct amount of cruise-timing, EFI will be of very little benefit. Whether or not your 198 can generate enough power to cruise down there, I cannot say. You cannot take the rpm down so low, that it requires WOT to maintain your desired cruise-rpm. Well I mean you could, but...

IMO, putting an overdrive in it, together with re-engineering the ignition timing curve, will reap far more benefits; but if you get below about 65=2200, you will need some kind of a stand-alone timing computer.
Why?
Because by that rpm, the factory distributor cannot be re-engineered to supply the correct amount of Cruise-timing AND Power-timing AND Part Throttle timing, all with the same, even modified, factory guts. And without the correct Cruise Timing, fuel-economy will just get worse (or at least not get any better) because the throttle will have to be way too far open to get the required cruise-power. So what you gained in rpm-reduction, you lose in the inefficiency of the loss of Cruise-timing.

To see how this works;
Rev your engine up to 2000 rpm and fix it there. Now just grab the distributor and start advancing the timing without regard to the actual numbers.
As the rpm goes up, reduce it back to 2000.
When the rpm no longer rises with more timing, now your timing is optimized for that rpm. NOW read the balancer marks. Don't be surprised to see a number well over 35degrees, and possibly closer to 40/50 degrees. My 360SBM, for example, at one time, liked 60 degrees@2000 .. Of course, under load this will change slightly, but may change back again as you lean out the cruise circuit.
The key to fuel economy lies in rpm reduction and adequate ignition advance, THEN AFR optimization. To start with the AFR, you might as well stick with a carb.
The above test will get your Cruise-timing ball-parked. But you cannot drive it when it is set to 54*@2000! else you may rattle all your piston skirts straight into the oilpan.....
To get numbers as high as 54 degrees, you have to modify the V-can which maxes out at between 20 to 24 degrees; leaving ~34 in the mechanical. Which can be done... but 34*@2000 will detonate at full-power, and possibly even down to as low as quarter-throttle. Detonation must be avoided at ALL COST; cuz it breaks stuff.
This is the reason for the stand-alone timing computer.
Any way, that is my spiel, hope you get something out of it.
Happy HotRodding.

EDIT
BTW; with a manual trans, you are already set up for an F-body A833od. It has about the same ratios as your current trans, but has a .73overdrive gear. From 65=2500, that od gear would drop your Rs to .73 x 2500=1825 by the math.
The only hiccups are your shifter, and probably/possibly, the BH and driveshaft slip-yoke. That .73overdrive, by percentage is said to increase your fuel-economy by one-half of the rpm reduction, so that comes to;
1 less .73 times .5= 13.5%. If you are already getting say 20mpgs, then the od might be worth 2.7mpgs, after you get the timing worked out. Your TBI-EFI by itself with no other changes is not likely to touch that.
I buy my A833-ods at swap-meets with beer-money, cuz guys often don't want to drag them home anymore. I scored a minty one once for $50; the guts were like new.
You can modify your column-shifter for 4 gears but would have to figure out something else for reverse. It's already been done by at least one FABO member.
If you have a B&T front yoke, that just leaves changing that out.
If you were so inclined, you could increase your rear gear, to end up at 65=2000 to 2200, and gain some off-the-line performance. Say 2200, that makes it possible to modify your current distributor closer to optimum, and could be fully optimized with just a dial-back(DB) timing module used strictly for cruising. Mine has a working range of 15 degrees. I can change my timing from the front seat to anywhere in that range.
Say you modify your V-can to 20*, and set the DB to 10*, and say your engine likes 54* at a cruise of 65=2200. You got up to 20+10 =30 degrees already, so in the mechanical, you just need 54 less 30= 24@2200 and that might be just fine at Full-Power. If not, you still have 5* of retard in the DB to play with. I love that tool!
The only hiccup with this tool is to remember to Zero it when you come off the hi-way. Mine, a Jacob's, is now no longer being manufactured, (at least I cannot find it on the Net) ...... but MSD has one.
 
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Johnny71dusty

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I understand - but I need adapter either way to go from single barrel to a 2 to even have option of efi . Asking for where to find that adapter . I see plenty folks on YouTube use one but they don’t list what part it is
 

Johnny71dusty

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Aj though i appreciate you this is why this forum drives me nuts. Asking where to find the adapter . People want to Constantly want to change my mind or a set my simple questions with more questions . I don’t care if people think a wheel I want is dumb or not , or If something isn’t original options , or why I shouldn’t put a 4bbl on a slant 6 or not . I’m not asking people’s opinions . Generally asking about facts , yes / no , or where to find a part . I e a radiator for my car , I didn’t need anyone telling me or asking me if I did that or this . I needed a radiator that’s it simple . Really hate this forum because of this . I asking for a link to a part to make a 1bbl slant intake to a 2bbl . That’s it.
 

Johnny71dusty

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This reply is full of such great info . But non of which I wanted or asked for and nearly every post I make I get reply’s like this or someone telling me why I shouldn’t do it .
 

Killer6

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This reply is full of such great info . But non of which I wanted or asked for and nearly every post I make I get reply’s like this or someone telling me why I shouldn’t do it .
I would suggest placing an ad in the Parts Wanted forum here, and the same over at slantsix.org's site. Be sure to list what base dimensions You want/type of 2bbl You've got in mind, will help save time for all parties.
Don't mind AJ, he may have just hit the "tech-crack" pipe before posting, lol! I appreciate His zeal to give guidance, & when I have time to read some of those, I get a nugget I either didn't know/think of or forgot.....50/50 possibilty there!!..
On the plus side You managed a single sentance response from @AJ/FormS, I'd screenshot, save, print & frame that.:poke:
 

RustyRatRod

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I understand - but I need adapter either way to go from single barrel to a 2 to even have option of efi . Asking for where to find that adapter . I see plenty folks on YouTube use one but they don’t list what part it is
Summit. Trans Dapt. One to two barrel adapter. I have two of them on my 331 Hemi.
 

RustyRatRod

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I’d to

u look at their pic it can’t be used on slant 6 manifold as it’s a 2 bolt only hook up and this adapter has 4 . But photo could be not actual product
Just because it has four bolt holes on the one barrel side doesn't mean it won't work. If two of those slotted bolt holes will line up with the slant 6 bolt holes on the intake it will bolt on and work. My only worry would be how high they sit and whether the hood would close.
 

Johnny71dusty

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Just because it has four bolt holes on the one barrel side doesn't mean it won't work. If two of those slotted bolt holes will line up with the slant 6 bolt holes on the intake it will bolt on and work. My only worry would be how high they sit and whether the hood would close.
That worries me too . They said it won’t worl with a slant six . So o don’t know what some these guys are using and I’ve not done one in 14 years or more but I don’t remember it being this hard to just google and find one a s it worked perfect.
 

RustyRatRod

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That worries me too . They said it won’t worl with a slant six . So o don’t know what some these guys are using and I’ve not done one in 14 years or more but I don’t remember it being this hard to just google and find one a s it worked perfect.
Ok. Well I guess you'll not find out for yourself then. lol
 

RustyRatRod

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It's the closest thing out there and it's cheap. I'm certain it can be made to work. Did you bother to ask what the one barrel side bolt pattern is? From center to center of the 2 slots across from each other? I would be willing to bet no one you talked to has ever even seen a slant 6. If everybody just laid down when someone else said something wouldn't work, hot rodding wouldn't even exist. Maybe Tiddly Winks or stamp collecting is more your speed?
 

Charrlie_S

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I have been out in the shop, trying to organize parts, and guess what I found? A 1bbl to 2bbl adapter. It is similar to the ones linked to, but the holes are not slotted.
It has a part number of 5710 on it. I think it is Offie. FLATHEAD HOT RAT ROD TRI-POWER CARB ADAPTER-4 BOLT TO 2 BOLT CA-16 OFFY 5710 | eBay
It will take a slant six 1 bbl holley carb. I don't have a 2bbl carb handy to check that. It is 1.5 inches tall. If your interested PM me.
PS: It is used.
 

bcschief

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Years ago, there was an article on slantsix.org where they modified a stock slant six cast iron manifold to take a 2-barrel carb, I just looked but I can't find it. Basically, you purchased an adapter and used it as a pattern to mark the manifold then drilled a series of 1/8 inch holes around the perimeter and then broke out the center and then ground it out smooth. Maybe someone has a copy of the article. I think this also was in the slant six quarterly newsletter (pre internet)
 

RustyRatRod

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Years ago, there was an article on slantsix.org where they modified a stock slant six cast iron manifold to take a 2-barrel carb, I just looked but I can't find it. Basically, you purchased an adapter and used it as a pattern to mark the manifold then drilled a series of 1/8 inch holes around the perimeter and then broke out the center and then ground it out smooth. Maybe someone has a copy of the article. I think this also was in the slant six quarterly newsletter (pre internet)
It actually works pretty good. @slantsixdan just posted that article here somewhere very recently.
 

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