you don`t need an adaptor to put a square pattern carb on a four bbl intake, unless you are trying a spread bore,in that case the screw on intake top must be missing.
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| Carb Adapter For Offy and Clifford https://slantsix.org/forum/viewtopic.php?t=25869 |
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| Author: | Rug_Trucker [ Thu Nov 15, 2007 3:32 pm ] |
| Post subject: | Carb Adapter For Offy and Clifford |
What is the deal with 4bbl intakes for slants. Do you need an adapter to bolt on a carb? Is that both brands? Is there an advantage to running an adapter on one of these to a 2bbl VS the MP M1 2bbl intake? |
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| Author: | terrylittlejohn [ Thu Nov 15, 2007 5:03 pm ] |
| Post subject: | slantsix manifold |
you don`t need an adaptor to put a square pattern carb on a four bbl intake, unless you are trying a spread bore,in that case the screw on intake top must be missing.
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| Author: | slantzilla [ Thu Nov 15, 2007 5:21 pm ] |
| Post subject: | |
Yes, both intakes require a carb mounting plate. I have only seen a 4bbl plate for an Offy, but Clifford has at least 2 different ones that I know of. 
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| Author: | Rug_Trucker [ Thu Nov 15, 2007 6:01 pm ] |
| Post subject: | |
Quote: Yes, both intakes require a carb mounting plate. I have only seen a 4bbl plate for an Offy, but Clifford has at least 2 different ones that I know of.
That just doesn't make sense. Does the plates come with the Offy and Clifford new? Or is that an extra expense? |
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| Author: | Joshie225 [ Thu Nov 15, 2007 7:12 pm ] |
| Post subject: | |
it makes perfect sense if you know that the pattern on the manifold actually matches an old Rochester 4-jet. These manifolds were designed a long time ago and have been adapted for use with 'modern' Holley carbs. The Offy comes new with the plate, the Clifford plate you used to have to buy by itself and probably still do since you have a choice of 2 or 4bbl. |
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| Author: | Rug_Trucker [ Thu Nov 15, 2007 7:43 pm ] |
| Post subject: | |
Quote: it makes perfect sense if you know that the pattern on the manifold actually matches an old Rochester 4-jet.
Maybe I can bolt a '66 383 tiny AFB or even tinier Buick '67 AFB. I have a 600 Eddie AFB in ths shop. And these others. They have tops that take a 4 1/8th inch air cleaner.  I'll have to measure the bolt patterns. |
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| Author: | Joshie225 [ Thu Nov 15, 2007 9:29 pm ] |
| Post subject: | |
Sorry, no, it won't fit. |
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| Author: | rock [ Fri Nov 16, 2007 9:49 am ] |
| Post subject: | rug trucker, make one this way |
Rug trucker, Joshie is right...the Offy has a set of 4 holes that are closer together than those for the Holley base. Further, if you want to rotate the Holley to get the primaries parallel with the cylinders, you need an adapter. I make my own because I use an inch thick one made from an 8 inch square aluminum plate (from McMaster Carr) for heat blocking. You need to drill the adapter plate for Offy holes and counterbore them on top to use allen head screws to bolt your adapter to the manifold. The holes for the pattern you choose for your carb (parallel or perpendicular) are drilled, then counterbored underneath so you can set hex head nuts underneath and use studs to attach a 2 inch stock Holley 4 hole 4bbl adapter. If you are making your base plate, you will have to either drill 4 holes, one for each throat, or mill out a square hole for the throats to discharge into. Drilling separate throat holes requires either a BIG drill bit or a pal at a machine shop as the holes are either 1 3/8 or 1 7/16, I don't remember exactly now. I stack Holley 2 inch adapters on top of that plate for more height. I know you can buy an adapter, but it is not as "adaptable" as what you can make. rock '64d100 |
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| Author: | Rug_Trucker [ Fri Nov 16, 2007 10:52 am ] |
| Post subject: | |
The Buick carb bolt pattern is 5 5/8" front to back, 4 1/4" left to right. The '66 383 carb is 5 5/8" F to B, and has a dual pattern either 5 1/4", or 5 1/4" L to R The Buick is smaller in the throttle plates. Maybe a 400 something cfm. So I will need to adapt to run one of these? |
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| Author: | slantzilla [ Fri Nov 16, 2007 2:22 pm ] |
| Post subject: | |
Quote: The Buick carb bolt pattern is 5 5/8" front to back, 4 1/4" left to right.
The carb plate that comes with the Offy has both the AFB and Holley patterns.The '66 383 carb is 5 5/8" F to B, and has a dual pattern either 5 1/4", or 5 1/4" L to R The Buick is smaller in the throttle plates. Maybe a 400 something cfm. So I will need to adapt to run one of these? The 4bbl plate for the Clifford does too. You are supposed to be able to rotate the plate on a Clifford to mount the carb sideways, but I can not confirm that. I tried it once and can't remember if it worked or not.
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| Author: | AndyZ [ Fri Nov 16, 2007 2:48 pm ] |
| Post subject: | |
Adapter bolt pattern is not square on my Offy adapter plate. This an older Offy intake and they may have changed some things since. I don't have the dimensions here but I turned the plate 90 degrees and had to re-drill. This bolt pattern is a legacy from the old Rochester from ~ 1967 and earlier. |
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| Author: | terrylittlejohn [ Fri Nov 16, 2007 3:26 pm ] |
| Post subject: | adapter |
if you fabrication skills are not up to the task just order a 4hole 1in thick aluminum spacer from summit it`s only $18 and drill it to match the bolt pattern on your intake 
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| Author: | FrankRaso [ Fri Nov 16, 2007 6:51 pm ] |
| Post subject: | |
You can redrill that adapter plate but hood clearance is a problem with Slant Sixes (at least in the narrow bodies). You may need to mill the 1" thick spacer down to 1/2" so your air cleaner won't hit the hood brace. I have a 1/2" thick, 90° square bore adapter plate designed to fit the Offenhauser intake manifold available for C$65 in case anyone is interested. 
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| Author: | Rug_Trucker [ Sat Nov 17, 2007 5:34 am ] |
| Post subject: | |
The reason I am asking. I am not quite in the position to buy right now. I would prefer used. And want to make sure I get all the parts, or know where to get them. I saw a pic of a used Clifford the other day. No plate. AFAI could see. Is their a plus to turning the carb? Which way do the primaries go? To the driver fender? |
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| Author: | Rug_Trucker [ Tue Nov 20, 2007 5:48 pm ] |
| Post subject: | |
Quote: The Buick carb bolt pattern is 5 5/8" front to back, 4 1/4" left to right.
I was at www.offyparts.com and the adapter they sell is for a 3 7/8" X 3 3/4" carb. It adapts my carbs or regular Holleys and Carters to the small size slant intake.The '66 383 carb is 5 5/8" F to B, and has a dual pattern either 5 1/4", or 5 1/4" L to R The Buick is smaller in the throttle plates. Maybe a 400 something cfm. So I will need to adapt to run one of these? Does that come with the new intake from Offy? |
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