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| BBD too rich at low speed, too lean at high speed https://www.slantsix.org/forum/viewtopic.php?t=66117 |
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| Author: | Jase [ Wed Aug 11, 2021 5:20 pm ] |
| Post subject: | Re: BBD too rich at low speed, too lean at high speed |
Quote: IMO, it is a waste of time trying to make the BBD work. Your best bet is to buy a Rochester 2GC to Holley 2300 adapter plate. Then find an AMC version of the Autolite 2100 with 1.08 on the throttle bores. Rebuild this with a kit from an early '70s Jeep with a 304. Change the jets to #46. Bolt it on, adjust/make linkage as needed. Then drive the car. This is the best carburetor you can use.
Interesting perspective, and maybe a very good idea... I would not recognize one if I tripped over one at the salvage yard... so time for me to do some research!I have heard/read that the Autolite is a very good carb, but do not understand why it is regarded as highly as it is. |
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| Author: | volaredon [ Wed Aug 11, 2021 6:24 pm ] |
| Post subject: | Re: BBD too rich at low speed, too lean at high speed |
Somebody here had a glut of NOS BBD carbs last summer, the real thing. Application was mid-late 70s 318 truck with (what was then) "heavy duty emissions, meaning (again Back then) "minimal" emissions. I bought 2. One is still wrapped in original materials, going onto my truck with it's new engine. The other is running around on my son's 80 D-150 (slant powered) and running great, big difference noted as soon as we swapped it into the truck in place of the original Holley 1 barrel. I'd rather build one from many originals if need be vs take a chance on 1 Chinese lookalike. |
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| Author: | kesteb [ Fri Aug 13, 2021 4:13 pm ] |
| Post subject: | Re: BBD too rich at low speed, too lean at high speed |
You can buy kits on ebay to do the conversion. They are for Jeeps with the 258 engine. The Jeep guys love them, because it cures all the problems that their version of the BBD had. Our problem is that nobody makes "performance" parts for these carbs. Of course some of them can use AFB jets and some of them can use AFB stepup springs. But by the time they are "remanufactured" there is no telling what you are getting and most of them have worn out throttle shafts by now, which is not fixed in the "remanufacture" process. Time has taken it's toll on a once great carburetor. They are now junk. |
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| Author: | rich006 [ Wed Sep 15, 2021 7:51 am ] |
| Post subject: | Re: BBD too rich at low speed, too lean at high speed |
I took the junk BBD to the machinist at my workplace and he didn't think he could rebush the throttle shaft. So I bought an actual Slant Six BBD from United Automotive Remanufacturing, and it works perfectly. Drivability is great, and no ping. I can set the idle AFR to 13 or 14 and it's around 12 at WOT. There's just a tiny bit of play in the throttle shaft, but the vacuum holds at 18.5 inches at idle. |
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| Author: | SpaceFrank [ Fri Sep 17, 2021 11:53 am ] |
| Post subject: | Re: BBD too rich at low speed, too lean at high speed |
Quote: I took the junk BBD to the machinist at my workplace and he didn't think he could rebush the throttle shaft. So I bought an actual Slant Six BBD from United Automotive Remanufacturing, and it works perfectly. Drivability is great, and no ping. I can set the idle AFR to 13 or 14 and it's around 12 at WOT. There's just a tiny bit of play in the throttle shaft, but the vacuum holds at 18.5 inches at idle.
Great news! Thanks for coming back with a report on a good vendor.Happy driving! |
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