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Old 02-08-2021, 07:14 PM   #1
old51sedan
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Holley Carb adapter

Recently bought a offenhauser 4 barrel intake for my 292 with adapter. Just bought a rebuilt Holley 550 4 barrel carb. Low and behold it sits on the manifold sideways. I would like it to sit like a V8 with the linkage on the drivers side. I've been looking at adapters to correct this, I'm thinking they must make one, but no luck so far. Has anyone else had this situation, if so what did you do to correct it?
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Old 02-08-2021, 07:26 PM   #2
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Re: Holley Carb adapter

As far as I know they don’t make one.
I saw an adaptor on a thread somewhere that was made from 1/4 inch flat plate. Holes drilled to bolt the Holley on and counter sunk holes to adapt the plate to the intake.
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Old 02-08-2021, 07:30 PM   #3
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Re: Holley Carb adapter

Do you need an adapter to mount the carb or a linkage adapter?
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Old 02-08-2021, 08:44 PM   #4
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Re: Holley Carb adapter

So you want the primaries to open up and feed cylinders 1-2-3, and then the secondaries feed 4-5-6?
I prefer the carb to face the drivers side fender...
I ran a Holley 4160 [R8007] 390 CFM for 25 years on that Offenhauser intake. I had to saw off the ford-style automatic transmission kickdown lever, but since it's a Chevy and I run a manual that didn't matter. When I rebuilt in 2005, I went to an Edelbrock [500 CFM], as my 390 Holley was shot.
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Old 02-08-2021, 08:53 PM   #5
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Re: Holley Carb adapter

Theres a company called, Transdapt that might get you there, if they are still in business.
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Old 02-08-2021, 09:04 PM   #6
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Re: Holley Carb adapter

I suggest modifying the '68 accelerator push rod set up to '72 style cable throttle. I ran the old push/pull rod for a long time but it was cr@ppy. Linkages came loose, small bits fell off, it even iced up once in the mountains. Too much of a Rube Goldberg. I changed to a cable and it was never smoother. And you can mount your carb in any orientation you want.
This is the cable I used. A GM cable/gas pedal assembly off a '71/'72 truck was used in the cab.
I used a Jeg's throttle return spring to retract the spring on the engine side. [A big screendoor spring to the brake master cylinder was ruled out as too Retro-Jethro].
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Old 02-09-2021, 10:19 AM   #7
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Re: Holley Carb adapter

Quote:
Originally Posted by '68OrangeSunshine View Post
I suggest modifying the '68 accelerator push rod set up to '72 style cable throttle. I ran the old push/pull rod for a long time but it was cr@ppy. Linkages came loose, small bits fell off, it even iced up once in the mountains. Too much of a Rube Goldberg. I changed to a cable and it was never smoother. And you can mount your carb in any orientation you want.
This is the cable I used. A GM cable/gas pedal assembly off a '71/'72 truck was used in the cab.
I used a Jeg's throttle return spring to retract the spring on the engine side. [A big screendoor spring to the brake master cylinder was ruled out as too Retro-Jethro].
I'm looking for an adapter so that the carb will face the front of the truck. Are the offenhauser manifolds set up so that all brands of carbs have to fit sideways? I was thinking that I would be better off running a cable instead of the old linkage, I appreciate the picture of the cable. Do I have to buy a different manifold brand if They don't make an adapter or have a new adapter made?
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Old 02-09-2021, 11:06 AM   #8
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Re: Holley Carb adapter

The offy intake turns them all sideways.
You’ll need to make an adaptor to change that.
Clifford intake is set up to do what you want.
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Old 02-09-2021, 11:14 AM   #9
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Re: Holley Carb adapter

Quote:
Originally Posted by geezer#99 View Post
The offy intake turns them all sideways.
You’ll need to make an adaptor to change that.
Clifford intake is set up to do what you want.
Dang it, I appreciate you answer, but don't like it. HAHAHA I just bought this intake, I would have bought the Clifford, but they were out of stock and I was told that they don't work well with my cast iron headers. It seems like someone would make a adapter for this, I can't be the only one with this situation....
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Old 02-09-2021, 11:40 AM   #10
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Re: Holley Carb adapter

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Originally Posted by '68OrangeSunshine View Post
I suggest modifying the '68 accelerator push rod set up to '72 style cable throttle. I ran the old push/pull rod for a long time but it was cr@ppy. Linkages came loose, small bits fell off, it even iced up once in the mountains. Too much of a Rube Goldberg. I changed to a cable and it was never smoother. And you can mount your carb in any orientation you want.
This is the cable I used. A GM cable/gas pedal assembly off a '71/'72 truck was used in the cab.
I used a Jeg's throttle return spring to retract the spring on the engine side. [A big screendoor spring to the brake master cylinder was ruled out as too Retro-Jethro].
I second the pedal upgrade. I just did this on my 68 and I wish I had done this YEARS ago. No more crappy linkage and I routed my throttle cable the way I wanted it routed. The only thing I'd suggest is spend the money on a quality custom cable, either from a shop, or one of the DIY kits. I had a HELL of a time finding one that fit. You'll be so happy you did it and you'll never look back at the old linkage
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Old 02-09-2021, 12:47 PM   #11
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Re: Holley Carb adapter

Here's a bell crank arrangement I made for mine. I believe the aluminum elbow came with the exhaust manifold but I had to modify it. This works ok but it took a lot of trial and error and I plan to change to a cable setup when I have time.
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Old 02-09-2021, 04:23 PM   #12
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Re: Holley Carb adapter

Quote:
Originally Posted by old51sedan View Post
Recently bought a offenhauser 4 barrel intake for my 292 with adapter. Just bought a rebuilt Holley 550 4 barrel carb. Low and behold it sits on the manifold sideways. I would like it to sit like a V8 with the linkage on the drivers side. I've been looking at adapters to correct this, I'm thinking they must make one, but no luck so far. Has anyone else had this situation, if so what did you do to correct it?

http://t6performance.com/

This guy (Larry P.....) makes a new plate or modifies your original Offy plate so that it can rotate the carb 90 degrees. I have heard nothing but good from him on the 6 banger boards and I talked to him a good hour when I was planning on twisting mine around. I have not done it yet because on on install in an 81 truck, the factory cable comes in that way for the stock integrated 2bbl setup.
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Old 02-09-2021, 05:46 PM   #13
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Re: Holley Carb adapter

I've met Larry Page. Really nice guy. He used to be Pres of the Daytona chapter of Inliners International. He helped me [via emails] on tech questions when I was rebuilding my present 292 from 2002 -2005. The Man knows a lot about the Chevy L6 engine.
Larry also participates in this website as ''Twisted6'', usually on the 60-66 forum.
Still wondering if there's any advantage from having the primaries opening over 1-2-3 and secondaries over 4-5-6 with a carb-to-front orientation?
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Old 02-09-2021, 06:33 PM   #14
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Re: Holley Carb adapter

From a few folks I talked to, unless your racing you probably won't notice much difference. I think Larry is working on a full EFI setup now for the 250/292.
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Old 02-09-2021, 08:18 PM   #15
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Re: Holley Carb adapter

Quote:
Originally Posted by '68OrangeSunshine View Post
I've met Larry Page. Really nice guy. He used to be Pres of the Daytona chapter of Inliners International. He helped me [via emails] on tech questions when I was rebuilding my present 292 from 2002 -2005. The Man knows a lot about the Chevy L6 engine.
Larry also participates in this website as ''Twisted6'', usually on the 60-66 forum.
Still wondering if there's any advantage from having the primaries opening over 1-2-3 and secondaries over 4-5-6 with a carb-to-front orientation?
Likely if you where to measure you’d see the primary on a front facing carb is less than half an inch from a sideways set up.
The offy is a single plane style with plenum and runners all open.
All six cylinders see the primaries or the secondaries at wot.
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Old 02-09-2021, 10:00 PM   #16
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Re: Holley Carb adapter

My stock carb on my 292 is shot. What is available in larger CFM but without an Offenhauser intake? Is there something available to bolt on to the stock intake? Searching comes up with 4 barrels with rectangle mounts and 4 bolts. My stock intake is round with 2 bolts. Or am I dreaming?
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Old 02-10-2021, 12:24 AM   #17
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Re: Holley Carb adapter

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Originally Posted by mikelcobb0@gmail.com View Post
My stock carb on my 292 is shot. What is available in larger CFM but without an Offenhauser intake? Is there something available to bolt on to the stock intake? Searching comes up with 4 barrels with rectangle mounts and 4 bolts. My stock intake is round with 2 bolts. Or am I dreaming?
Sorry, Mike. There's a reason a lot of us have gone to 4 barrel set ups. Unless you or someone-you-know is a wizard welding cast-iron manifolds, there are no 2 barrel options with the stock intake. Exception: there is a 2-into-1 adapter that can bolt onto the stock intake, but it's about 3-1/2'' taller at the base, and there are few 2-barrel carbs for that application. You want about 390 CFM at WOT for a 292.
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Old 02-10-2021, 12:34 AM   #18
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Re: Holley Carb adapter

This one is about 1 1/2 inches tall.
Will run a 2gc.

https://www.tdotperformance.ca/trans...SABEgLHhPD_BwE
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Old 02-10-2021, 10:02 AM   #19
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Re: Holley Carb adapter

Quote:
Originally Posted by geezer#99 View Post
Likely if you where to measure you’d see the primary on a front facing carb is less than half an inch from a sideways set up.
The offy is a single plane style with plenum and runners all open.
All six cylinders see the primaries or the secondaries at wot.
Thanks guys for the replies. It's hard for me to believe that there's not an adapter plate made for this intake. It looks like I have 2 choices, buy a Clifford, or have an adapter made. Anyone want to trade there Clifford? My buddy from NY is here in Florida and he swears we will find an adapter plate. I'll let you know how the rest of the story turns out. I definitely want the carb sitting on the manifold facing to the front, I just think it's cleaner looking.
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Old 02-10-2021, 04:00 PM   #20
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Re: Holley Carb adapter

Quote:
Originally Posted by geezer#99 View Post
This one is about 1 1/2 inches tall.
Will run a 2gc.

https://www.tdotperformance.ca/trans...SABEgLHhPD_BwE
OK. That's the one. I stand corrected on size. I have an Offy one out back, but I had a guy weld a plate on it for a Holley/Weber progressive 2-Bbl off a Vega, but the speed shop told me it would never have the CFMs for a 292, so I got a Holley 390 4-Bbl.
Thanks, Geezer.
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Old 02-10-2021, 04:37 PM   #21
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Re: Holley Carb adapter

Thanks Geezer. I have it in a shopping cart. Now to find a 2 barrel at 390 CFM. Thanks!
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Old 02-21-2021, 07:32 PM   #22
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Re: Holley Carb adapter

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Old 02-22-2021, 11:14 AM   #23
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Re: Holley Carb adapter

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Originally Posted by old51sedan View Post
Thanks guys for the replies. It's hard for me to believe that there's not an adapter plate made for this intake. It looks like I have 2 choices, buy a Clifford, or have an adapter made. Anyone want to trade there Clifford? My buddy from NY is here in Florida and he swears we will find an adapter plate. I'll let you know how the rest of the story turns out. I definitely want the carb sitting on the manifold facing to the front, I just think it's cleaner looking.
Just thought I'd give an update to this thread. After hitting most swap meets in the last couple of months without finding any such animal, I decided to take the original plate that came on the manifold to the welding shop. They welded the four original holes shut, I then marked it with the gasket and center punched the holes in the plate. Then drilled the holes, countersunk them and it was ready to bolt on. While out looking also picked up an adapter to a 2 barrel in case I wanted to go that way. Ended up buying a newly rebuilt Holley 550 cfm with electric chock, so I guess were ready to go.
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Old 02-22-2021, 09:12 PM   #24
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Re: Holley Carb adapter

I had my Holley 8007, 390 CFM turned so the primaries were inboard and the throttle lever over the Rear intake. Required some surgery.
What ever makes it work for you.
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