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Offenhauser intake manifolds

General engine tech -- Drag Racing to Circle Track

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1980RS
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Re: Offenhauser intake manifolds

Post by 1980RS »

bthomas wrote: Wed Jun 09, 2021 12:05 pm I’ll be using one, although it’s not a run of the mill 4bbl intake. Crossram setup with Holley efi. I have a 67 camaro and wanted the trans am look.

Image
I have the same intake that I was going to sell, you just made me change my mind with that picture to keep it. That is fricken cool, I love it.
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Re: Offenhauser intake manifolds

Post by n2omike »

Back before the Ford 302 Victor Jr came out around 1991, the top dog SBF intake was a heavily modified Offy Port-o-Sonic. It looks about like a smaller version of the Vic Jr, but is FAR rougher and crude inside... and needs a lot of work.

As for Offy in general, they are antique designs, and have been drastically surpassed by any semi-modern company that has made any kind of effort for a particular platform.
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Re: Offenhauser intake manifolds

Post by Adger Smith »

429 & 460 Port-O- Sonic were pretty good back in the day.
Really a little ahead and very similar to the open plenum spider intakes of today.
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Re: Offenhauser intake manifolds

Post by hoodeng »

There you go n2omike! I ran a Port-o-Sonic + 0-1850 on a 302 Cleveland in a ZF Fairlane coming up forty years ago, TQ20 cam, etc. For what it was it went great.
It was not even on the radar to get it on the dyno back then, the only engines that i knew of then were getting crated and sent to Dyno Don at Repco in Melbourne for use in F5000. Now, i don't even go near an opinion on an engine till after it comes off the brake.

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Re: Offenhauser intake manifolds

Post by 408 Nova »

Walter R. Malik wrote: Wed Jun 09, 2021 4:10 pm I am gonna make a guess here that none of you have ever built and ran a carbureted small block Mopar Super Stock engine with a modified Port-O-Sonic.

For Dominator proponents; the small block Chevy "Super-Sonic" was a pretty good manifold, too.

Their "Turbo-Thrust" tunnel rams work well, also.

Not many STREET manifolds, though.
That Super Sonic manifold doesn't look too far off an Edelbrock 2970 IMO, and I wouldn't be afraid to try one for the cool factor of having an Offenhauser manifold under the hood.

Plus, I'll bet performance might not be that far off either. And would probably work well ported if needed.
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Re: Offenhauser intake manifolds

Post by BOOT »

1980RS wrote: Wed Jun 09, 2021 12:00 pm I don't care, that frickin setup is cool. :mrgreen:
No offense to 1980RS but that is the problem with a lot of stuff, looks > actual performance and it spills into the aftermarket. Also why I've seen many many tunnel rams and slightly used giant race cams for cheap, prob came off a street car. Don't get me wrong I wanna try a tunnel ram someday for a street car with carbs not efi, think I could make one work good enough with my tuning skills these days.

A magazine did two big 20+ test of dual planes and single planes, not a very big diff and I sure if all intakes were cleaned up it would tighten up more. I mean if your looking for that last bit then honesty you really gotta test a few yourself cause I'm sure you could test 20 of the same exact intake out of the boxes and find a range of 5-15hp.

Heck I've herd bout a guy who gutted a blower and just ran it as an intake, still guess if that's what made him happy.
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Re: Offenhauser intake manifolds

Post by F-BIRD'88 »

The Offy intakes with short intake runner lengths "anti tuned" (eg: the 2x qjets dual quad single plane manifold)
design will want very high compression ratios and favour camshafts with specific valve open close events to max cylinder filling. Could be best siited for blow thru supercharged applications as not so dependant on long intake runner tuned designed induction.
The blower does the work....
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Re: Offenhauser intake manifolds

Post by 1980RS »

BOOT wrote: Fri Jun 11, 2021 2:24 am
1980RS wrote: Wed Jun 09, 2021 12:00 pm I don't care, that frickin setup is cool. :mrgreen:
No offense to 1980RS but that is the problem with a lot of stuff, looks > actual performance and it spills into the aftermarket. Also why I've seen many many tunnel rams and slightly used giant race cams for cheap, prob came off a street car. Don't get me wrong I wanna try a tunnel ram someday for a street car with carbs not efi, think I could make one work good enough with my tuning skills these days.

A magazine did two big 20+ test of dual planes and single planes, not a very big diff and I sure if all intakes were cleaned up it would tighten up more. I mean if your looking for that last bit then honesty you really gotta test a few yourself cause I'm sure you could test 20 of the same exact intake out of the boxes and find a range of 5-15hp.

Heck I've herd bout a guy who gutted a blower and just ran it as an intake, still guess if that's what made him happy.
People can say what they want about some of the big buck intakes being the best, that's why we test them and some of the old stuff will surprise you. Years ago I bought a Dart oval port intake for my BBC and all the reports was the it was the intake to run and made the most power at the time, well it was a big old DUD used it a couple of years ago, still was a DUD. My RPM intake was still quicker and faster than the Dart. $400 still sitting on the shelf as eye candy.
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Re: Offenhauser intake manifolds

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1980RS wrote: Sat Jun 12, 2021 1:37 am People can say what they want about some of the big buck intakes being the best, that's why we test them and some of the old stuff will surprise you. Years ago I bought a Dart oval port intake for my BBC and all the reports was the it was the intake to run and made the most power at the time, well it was a big old DUD used it a couple of years ago, still was a DUD. My RPM intake was still quicker and faster than the Dart. $400 still sitting on the shelf as eye candy.
It's hard to give an opinion on your combo w/o lots of details but again it's been proven many many times that people will buy RACE single planes for street cars when they should get a dual plane. I have a few brand new single planes waiting for a certain project to test and see what one works better for me. They will sit in their boxes until then and I will keep using dual planes on my street cars.

Of course some use a single plane NP on the street but they didn't just plop it on some random slapped together combo in a stock car.
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Re: Offenhauser intake manifolds

Post by 1980RS »

BOOT wrote: Sat Jun 12, 2021 11:58 am
1980RS wrote: Sat Jun 12, 2021 1:37 am People can say what they want about some of the big buck intakes being the best, that's why we test them and some of the old stuff will surprise you. Years ago I bought a Dart oval port intake for my BBC and all the reports was the it was the intake to run and made the most power at the time, well it was a big old DUD used it a couple of years ago, still was a DUD. My RPM intake was still quicker and faster than the Dart. $400 still sitting on the shelf as eye candy.
It's hard to give an opinion on your combo w/o lots of details but again it's been proven many many times that people will buy RACE single planes for street cars when they should get a dual plane. I have a few brand new single planes waiting for a certain project to test and see what one works better for me. They will sit in their boxes until then and I will keep using dual planes on my street cars.

Of course some use a single plane NP on the street but they didn't just plop it on some random slapped together combo in a stock car.
If you believe that theory on the single vs dual plane intake than you might be giving up power some place. Here is an example for you.
Last year I did a back to back single vs dual plane test.

Single plane result 11.29@116mph
Dual Plane result 11.26@117 and change mph. Everything else was the same on the car.

Both combos were optimized so it was a wash IMO.

My 358 Pump Gas SBC was pretty much the same results with the 300-36 vs the 330-25. The -36 made more low end and the the -25 made a little more top end. I have run single plane intakes on the street since forever and have never had one that I thought was super bad. Most of the problem were engines with a cam that way too BIG for the combination and no stall speed. If the combination does not all work together than it does not matter what intake you put on the car as it will be a dud.
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Re: Offenhauser intake manifolds

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1980RS wrote: Sat Jun 12, 2021 12:30 pm If you believe that theory on the single vs dual plane intake than you might be giving up power some place. Here is an example for you.
Last year I did a back to back single vs dual plane test.

Single plane result 11.29@116mph
Dual Plane result 11.26@117 and change mph. Everything else was the same on the car.

Both combos were optimized so it was a wash IMO.
What was the stall with the single plane, also what was the shift point/max rpm. Sounds like you proved your combo better suits a dual plane.
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Re: Offenhauser intake manifolds

Post by 1980RS »

BOOT wrote: Sat Jun 12, 2021 12:55 pm
1980RS wrote: Sat Jun 12, 2021 12:30 pm If you believe that theory on the single vs dual plane intake than you might be giving up power some place. Here is an example for you.
Last year I did a back to back single vs dual plane test.

Single plane result 11.29@116mph
Dual Plane result 11.26@117 and change mph. Everything else was the same on the car.

Both combos were optimized so it was a wash IMO.
What was the stall with the single plane, also what was the shift point/max rpm. Sounds like you proved your combo better suits a dual plane.
Stall was the same with both intakes, 48-5200rpm. Both intakes were within hundredths of each other so all it proves it that there is not much difference. With a cam switch and the Air Gap on a hot day the same combo went 11.16@118.26mph, have not tried the Single plane though. The Holley Strip Dominator 300-4 is one of the best intakes I have used, the Dart with a 750 QF the fall prior only mustered at 11.75@114.5mph all else the same on the car.
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Re: Offenhauser intake manifolds

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BOOT wrote: Sat Jun 12, 2021 12:55 pm also what was the shift point/max rpm. Sounds like you proved your combo better suits a dual plane.
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Re: Offenhauser intake manifolds

Post by engineguyBill »

Back in the 70's and 80's Offenhauser was the only source for tunnel ram manifolds for 425-455 Oldsmobile, 429-460 Ford. We built marine engines using these manifolds for flat bottom boats (both jet and v-drive) for customers running the Colorado River, i.e. Parker and Lake Havasu. These engines ran quite well with the Offenhauser tunnel rams and even the BBC with Offenhauser tunnel ram ran very well on these applications.
The Offenhauser four barrel intake manifold worked very well on 300 cu. in. Ford engines that we supplied to ski resorts for their chair lifts throughout the Western US.
Offenhauser offered many intake manifolds designed for the Quadrajet carburetor, including two four barrel (Q-jet) manifolds for many popular engines. Offy is now run by Trey Offenhauser (Fred Offenhauser III) and is located on Alhambra Blvd., in Los Angeles the same location they have occupied since the late 40's or so.
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