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Old 01-06-2003, 11:08 PM   #1
Blackhawkdc
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Offenhouser manifolds

Anyone know of where I can find information on Offenhouser manifolds? I'm looking for the high-rise Dual-quad they make for a 350.

Also, what do you guys think of putting a dual-qaud set up on a built 350? Engine specs in my signature. And what cam would you all recommend? I like the Lunati Bracket Master cam, but am looking for something with a little more lower end grunt.
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1969 Chev Short Step
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Old 01-06-2003, 11:20 PM   #2
mikep
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IMHO nothing will screw up a good running engine like throwing a set of dual quads on it. Tunnel rams are a different story as they actually make power in a hi rpm range but low rise dual quads really only belong on street rods and other stuff that never gets driven. If you want strong bottom end power then you really shouldnt even consider them. You can make a lot more power with a half decent single 4 bbl than you ever can with a low rise dual quad setup.

Save the money. You can pick up a set of pro lightning 200cc heads that will flow better than just about any streetable head ever made for $750. Throw those under your torker and you'll be looking at closer to 430-450 HP with that cam and you want have to be tuning and swearing all the time like you would with the dual quad setup.
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Old 01-07-2003, 12:00 AM   #3
RON WOODGEARD
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In the late 60's early 70's Chevrolet offered what they called a STR tunnel ram. (str meaning "street tunnel ram") They used it on their Z cars for real road racing. I don't remember the statistics on them, It's been too many years ago. I can't think of the manufacture either. (can anyone else help with this one?) It was a real screamer in the upper mid range. It was a Cross boss style like what ford did for their 302 Boss engines.

If you could find one of those that would be your best bet if you really want to run dual quads, but not a tunnel ram.
About a year ago I came upon a brand new Offy, dual quad tunnel ram on E-bay. It also is from the late 60's early 70's. It is the only tunnel ram that I know of that was actually designed to deliver power in the mid range. I'm going to run 2 holley 390 CFM carbs on it for the street. I'm still researching cams. Years ago when all I ran on the street was a tunnel ram, I ran this manifold with a Crane fireball cam with excellent results. I'll go something a little more radical this time though.
If you really want something that will deliver Power And economy, go to a fuel injection out of a 350 Camaro or trans Am. You'll need all of the wiring harness, and components, but you really can't beat it.

I myself am still stuck in the 60's, early 70's..

RON
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Old 01-07-2003, 12:10 AM   #4
Blackhawkdc
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the reason I'm searching for more info on Offenhouser is because I saw a dual-quad intake from them in the PAW catalog that appeared to be a mid-rise dual-quad manifold.

I've looked into the TPI setups, but would have to modify a Camaro/Firebird set up too much to be able to provide for the horsepower and torque that I'm trying to achieve, plus I'm stuck in the 60's and 70's myself.
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1969 Chev Short Step
425hp 350, TH400, big tires, fast truck
1979 Pontiac Trans Am
1991 Saturn SL1 - gas mileage! (and free)
1977 Buick LeSabre - for sale

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Old 01-07-2003, 12:22 AM   #5
mikep
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If your dead set on it then edelbrock offers a dual quad low rise manifold. I'll tell you though. Ever "manifold shootout" I have seen any of the major mags such as Hot Rod and PHR do they always throw in a dual quad setup. They ALWAYS finish at the back of the pack for power and torque. Summit gets $249 for one without the carbs.
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Old 01-07-2003, 12:33 AM   #6
bigjimzlll
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a cross ram will work...but tunning is a bear... and as Mike pointed out, you would make more power with a single 4 barrel..they do make a neat 3 duece set up that is very effecient.. i will try to find the link..of course there is nothing cooler than a 671
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Old 01-07-2003, 12:43 AM   #7
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To each his own
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Old 01-07-2003, 01:26 AM   #8
Blackhawkdc
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Quote:
Originally posted by bigjimzlll
of course there is nothing cooler than a 671
I agree, but I'm also going for something different, something not seen very often.
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Seth Petro

1969 Chev Short Step
425hp 350, TH400, big tires, fast truck
1979 Pontiac Trans Am
1991 Saturn SL1 - gas mileage! (and free)
1977 Buick LeSabre - for sale

May America bless God, and may God bless America
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Old 01-07-2003, 03:23 AM   #9
RON WOODGEARD
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Quote:
Originally posted by Blackhawkdc


I agree, but I'm also going for something different, something not seen very often.

My sentiments exactly........

RON
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Old 01-07-2003, 10:20 AM   #10
superchevy
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You might be better off with a larger cube smallblock.
A couple of years ago a friend of mine was running an old Offy midrise dualquad intake on a strong 400 small block with a pretty stout cam. It was set-up by a dragracing friend of his with 2 450cfm carbs. Was in a '67 Nova and it hauled a$$ and looked trick, too. The main thing was to not overcarb the engine. I remember them debating on getting a couple of 390cfm carbs, but I think he sold the car before he did that.
Anyways, it always got a rise at cruise night. I myself will trade a little horsepower to have a look different from everyone else, also.
My 2cents,
SC
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