Offenhauser big-block Buick intake manifolds unavailable ???

Dear V-8 Buick big-block experts,

It is a long story but I got a recommendation to look into the single plane intake manifolds from Offenhauser. Summit Racing certainly lists them but the two models I checked into are either unavailable:

http://www.summitracing.com/parts/ofy-5874

or won't ship until August:

http://www.summitracing.com/parts/ofy-5952/applications

I did a quick search of V-8 Buick and couldn't find a thread reporting this, never mind providing an explanation. I also searched Google news for "Offenhauser Sales Corp" to see if perhaps they were in some financial trouble. There were no hits at all for that name.

Does anybody know why these products aren't available at the moment?

Cheers, Edouard

 

That is something that doesn't exist. Weird.

 

Offenhauser business is solely run on paper. They have no computers. I have not talked to the owner for a few months now, Sherri does most of the ordering with Offenhauser. We have still been receiving product but it does take awhile. They now wait until they have a fair amount of back orders before they order castings. We stock the 2x4 intakes and we usually have to order a fair amount to get them to make them. The single plane 360 I believe is not a very popular intake for them, so I really don't think they will have one on the shelf, and I'm not into ordering as many as they would want. Don't think I have ever sold one.

 

Mike, from his link It looks like he is searching for a single 4500 flange Offenhauser intake...I could be wrong?

 

I'm guessing he wants a single plane intake to use with the throttle body EFI system he's using. General consensus is that they work much better with a single plane intake and you don't take the hit on low end torque like you do with a carb. Additionally I'm guessing an SP1 won't fit under the hood of his wagon so his only alternative is to find one of the Offy intakes assuming they have a lower installed height than the SP1.

Of course I'm just speculating....

 

A Poston S divider is the same thing, some body has one of them laying around im sure

 

Here's one for sale:

http://www.v8buick.com/showthread.php?299993-Poston-S-Divider-Aluminum-Intake&highlight=Poston+s

 

I looked into Offenhauser perhaps ten or fifteen years ago. I was on a cross-ram kick at the time.

Over the course of the company history, they've produced a huge number of interesting items.

HOWEVER, as far as I can tell, they're desperately trying to go out of business. There's no inventory. I believe that they wait for certain amount of backorder before having someone cast and machine the item. I'm saying that I do not believe they cast and machine in-house.

There's no R & D anymore. Whatever they sold thirty years ago is what they sell now...except for what they've actually discontinued.

There's a downloadable .pdf on-line catalog but it's a copy of the catalog from years ago.



Crap. Now I'm curious and I'll have to do some research. I hate when that happens.

First edit: Offenhauser catalog (ancient)
https://ccs.dogpile.com/ClickHandle...3&mid=9&hash=662CFCA33F85DA103630863FBC998FD4

Second edit: Contact info from yellowpages.com

Offenhauser Sales Corp
5300 Alhambra Ave,
Los Angeles, CA 90032

(323) 225-1307

 

Looking into THB EFI benefits (Re: Offenhauser big-block Buick intake manifolds)

Dear Guy, Mike, Larry, Ken, hugger, Frank, Schurkey, and V-8 Buick big-block experts,

Basically bingo. There is a slight twist in the tale as usual. I needed to ask a question on the FAST technical support forum and got pounced on by a guy over there who absolutely swears that a single plane intake manifold makes a huge improvement in performance. However, it appears that the situation is more complex than that. The throttle body designs of FAST do not appear to be as vulnerable to low end torque loss compared to say to some Holley models.

Indeed the TA-Performance SP1 won't fit on a 1964-67 Buick A-Body. It is 1-1/2" taller than the stock intake manifold and I already had to find a shorter filter element to avoid damaging the hood insulation with the air cleaner wing nut!

It does sound like this isn't something I'm going to want to pursuit. Perhaps I'll give Offenhauser a call just to see, but it would be mostly to satisfy my curiosity.

Thanks guys for the info! :TU:

Cheers, Edouard :beer

 

I think Joe Rivecco was selling this exact intake

http://www.v8buick.com/showthread.php?307019-offenhauser-455-intake-manifold&highlight=intake

there is a sale pending but you never know

 

I agree, had one that came with an engine I bought and sold the intake for little dollars.

 

Do I even want one? (Re: Offenhauser big-block Buick intake manifolds)

Dear Larry, John & Terry, Guy, and V-8 Buick parts hounds . . . .

That may be true, but do I even want one? o No:

The 64 dollar question is whether or not these old single plane manifolds might actually provide better performance for modern throttle body electronic fuel injection systems. There is somebody on the FAST technical support forum who is absolutely gaga for single plane intake manifolds, but . . . he never did explain exactly why. My advice from some of the FAST distributors is basically - "your mileage will very."

So the matter is mostly an issue of curiosity at the moment. I'd love to know if perhaps these old single plane intake manifold designs might have a new life because of throttle body fuel injection, but I'm not quite really to make the gamble myself. I've done this before and . . . . been burned! . . . :af:

Stay tuned!

Edouard :beer

 

I can tell you from my experience an Offy single plane is a low end torque killer. I bought one in my early days with BBB's and you could feel the low end go away. The stock intake easily out torqued it. Of course that was on a mild engine build. Some people have said that it runs about as good as an Edelbrock when you rev it up higher(6000). The Offy is not the same as a Poston intake which is basically a bad re-arranging of which cylinders are being isolated from each other. The Offy is single plane intake that is split down the middle of the plenum so the sides are completely separated. The big problem IMO is that it has no runner length to talk about because each runner, instead of being a constant steady cross-sectional dimension, actually acts like a funnel and since the carb pad height is the same height and location as stock it doesn't get a good single plane's attribute of a better shot down to the port that a higher mounted carb on a intake like the SP1 would. On top of that it doesn't get the dual planes #5&7 runners isolation from each other or even their slightly longer runner lengths(although the funnel effect is one problem that an Edelbrock Performer/B4B has also unlike the Performer RPM intakes that are available for Brand X engines). The single 4 bbl. Offy is pretty much the worst of all worlds.

That being said I really think you will still lose torque with a throttle body type fuel injection setup but it might mitigate some of the problems compared to a carburetor mounted on the intake but you will still have #5 port stealing from #7. The intakes can usually be found cheap enough but then you also find them where somebody thinks they have gold and want too much $$$. I think that if you can get one cheap enough it may be worth a try. I often thought that in a nitrous situation or, even better, a boosted situation the intake might work pretty good when hood clearance is an issue.

If you really want to try something a set of throttle bodies on a Offy dual quad intake would be a real fire breather especially with a pair of nitrous plates underneath. That is a straight shot down the old port. It would almost be like port fuel injection. If you needed big top end power the dual quad setup was the way to go before Kenne-Bell came up with the Wildcat single plane.

My only question as far as the FI setup goes is why would the setup be that much better on a single plane compared to a dual plane? If the FI system is just a better way of delivering the fuel/air compared to a carb then the attributes of the intake will still be the same. Generally speaking the dual plane will be better in the low to mid range and the single plane will do better as the rpm increases.

 

It's my understanding that multi-port FI is less affected by single vs dual plane intakes because the fuel is introduced at the intake port. TBI systems introduce fuel in the plenum same as a carb so I would think the same rules would apply.

 

Re: Do I even want one? (Re: Offenhauser big-block Buick intake manifolds)

The FAST guys probably aren't pulling trailers with a station wagon. Their mindset is max HP. Considering some of the problems you've had with this project I would leave your setup alone.

 

Ed, I would think the Edelbrock would be the best for you especially in regards to the small cam we installed.
On another note Offenhauser does machine the intakes in house.

 

Not sure how single plane helps (Re: Offenhauser big-block Buick intake manifolds)

Dear Mike, BillA, Mike, and V-8 Buick big-block experts,

Thanks for your thoughts on this one. I definitely wasn't planning to run out and by a single plane intake manifold tomorrow, but was simply trying to find out if there was any options for a 1964-67 Buick with a big block in it.

That's exactly the question to which I don't have a clear answer to. As best as I can understand it, the problem is that some throttle body fuel injection systems don't inject the fuel in the same way a traditional 4-barrel carburetor does. So hypothetically speaking, suppose you had a 4 injector system that only used some of the injectors when less fuel was needed. If when idling only one injector was being used, then one of the two planes in dual-plane intake manifold would be getting more gas than the other.

So the benefit - if any - is very much dependent on the throttle body you are using. If the throttle body was designed to provide fuel as a carburetor does, then the type of intake manifold wouldn't matter. Guys who are having this problem might be better off to change to a better designed throttle body instead of changing the intake manifold.

Well, the fellow who was hounding me to look into this on the FAST technical form was claiming he got a substantial boost in low-end torque. That would make sense if the throttle body was starving part of the engine at low RPM.

I'm definitely not planning to change the intake manifold anytime soon. I am making some changes right now to the fuel injection system to hopefully make my wagon easier to control when the engine is idling and as you start applying the throttle. Right now I'm a victim of all the power this engine can produce and have had some close calls simply trying to maneuver at low speed. Science and engineering agree on one principle: if you are trying to understand a situation, never change more than one thing at a time! So I'll file what I've learned about single-plane intake manifolds and perhaps revisit this topic sometime in the future.

Thanks again for all the helpful feedback! :TU:

Cheers, Edouard :beer

 

A strength of Buicks is that the intake tract is designed to assist in vaporizing fuel from it's introduction point, an efficiently vaporizing carb.

People get hung up on raw CFM's of flow.
The velocity of the intake tract, along with intentional swirl as well as the combustion chamber's shape coinciding to continue the MIXTURE MOTION (even as the piston ascends during the compression stroke) IS one of THE main strengths of this engine.
Also, they are cool .

Compare this to a Chevy small block from the 70's.
They have a lazy chamber and a manifold designed to help "shear" fuel back into the airstream via the use of 90* bends, in order to assist vaporization.
They respond well with raw airflow and high rpms (another way to vaporize fuel).
They also respond to "new" (lol) fast burn chambers and swirl dam ports (Look at AFR's ports for example).
Those engines show good increases by changing the intake to work WITH the rest of the new strategy.
One way of viewing things is that an "fast burn" or vortec chamber along with an aftermarket dual plane is akin to making it more "Buick like"...

A single plane intake will eliminate some restriction at higher rpms, where the natural benefit of a DP fades (keeps velocity high by exposing less of the carb to each opening intake valve, maintaining a stronger draw).

I doubt a SP would help much down low in a 455 based engine.
I can't see it helping vaporization or velocity.
There is many times more potential using the pull of a header than any intake "ramming" to fill cylinders (SP @ low rpm).
My understanding is that your current package is pretty good.

Are you considering multi-port injection?