Offenhauser 4bbl intake value

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Penstarpurist

Penstarpurist

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I've located a used offenhauser 4bbl intake for a /6. Guy was asking $200, but said he would take $150 for it with all the adapters. I have a few /6 engines laying around and may be using one in a build. So I was wondering if this is a good deal for it and if I do get it and use it, does it work with the stock exhaust or am I needing to upgrade that as well. I am assuming I could use fi tech with it as well.?.
 
150 is a good price for it. It is pretty much a copy of the stock intake with a 4 barrel plenum. The Clifford is the real HP piece, but for 90% of slant builds the Offy is great.
 
Awesome, should I plan to use headers/dual exhaust to get the most out of it?
 
Penstarpurist said:
Awesome, should I plan to use headers/dual exhaust to get the most out of it?
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I would certainly recommend it. "MY" personal opinion on straight sixes and smaller cube V8s is a well thought out, free flowing single exhaust as opposed to duals. IMO, especially with the slant six, the large diameter, mandrel bent if possible single exhaust will preform better. A good six into two header, with a Flowmaster wye pipe and a 2.5"-3.0" single exhaust would work great. Look up Flowmaster wye to get a feel for what they are. They have excellent scavenging properties. Whatever size the header collectors are, I would not reduce that. Just come off the collectors with the same size pipe and go into one larger one. Make sense?
 
Yes, that makes sense. I am going to try to get the intake tomorrow. The guy that listed it is 5 miles away from me. So should be an easy one to get. Unfortunately this is the only part he has left of his hopped up /6 valiant.
 
I agree with Rusty,Owned,Raced Slants for years.Clifford shorty headers are good (I wish other manufactures would step up and make Slant headers) 2 1/2'' single exhaust to the rear bumper. Snatch that Offy up !
 
You can use the Offy with a stock exhaust manifold. In my opinion, headers would be better performance-wise, but for street applications, it is beneficial to have the manifold heat (especially in colder climates). The factory exhaust manifold will flow quite nicely with a little porting, mostly to open up the size of the outlet to 2 1/4 -2 1/2 inches.
 
That is a smokin' deal, especially with the brackets. If you decide you don't want it, I'll be happy to take it off your hands! Lots of good advice above, especially regarding the exhaust. Headers will give you the most performance, but at the cost of no heat to the intake. If you're making a racer this is not an issue. If it's going to be street driven you'll probably be happier with the intake heat. You can reach a very agreeable compromise going with Dutra Duals - it's the best of both worlds with no downside.

I'm building my slant with a lot of upgrades, including the Offy intake and a whole bunch more. If you'd like to discuss details, feel free to send me a PM.
 
Well I got the intake, not sure if it is the great deal I was expecting it to be. It's an offenhauser /6 intake, but he said he didn't have the adaptors he thought he had with it. And no brackets, as I'm in uncharted territory here with a /6 build. Sure I have pulled alot of them out of cars, I've never looked back at them. What adapter do I need? What brackets? From what to where? I still paid the $150 as that's his bottom line on it as he said he was losing money at that. I am going to use it as I got it, but want to do it right and use the correct brackets and stuff. He said that some carbs will bolt directly onto it without the need for an adapter. Any advice on that?
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The guy just got back to me and said he found the adapter, so I will get it picked up shortly. Pleasant surprise for sure.
 
Nice score. Are the photis correct? That is a Clifford not an Offy.
 
Lol. Holy crap your right. It is a Clifford. He had called it an offenhauser in his ad and I had expected that and for some reason until you pointed it out I didn't even realize it. Haha, I'm getting old. Yes, these are the pictures of it. So I guess I bought a Clifford.
 
If you have a cable gas pedal it is easier to hook up carb. Rod type will require a good dose of rube Goldberg!
 
halfafish said:
Nice score. Are the photis correct? That is a Clifford not an Offy.
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Clifford makes great products for the slant six, also you can only run headers with this intake. my buddys 67 valiant has the water cooled intake with headers his car runs strong.
 
Penstarpurist said:
Lol. Holy crap your right. It is a Clifford. He had called it an offenhauser in his ad and I had expected that and for some reason until you pointed it out I didn't even realize it. Haha, I'm getting old. Yes, these are the pictures of it. So I guess I bought a Clifford.
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You got a real deal on that. That Clifford is the shizzle. It can support a lot of power.
 
Ditto on "single exhaust is fine". The HiPo 273 V-8 cars had a single exhaust. Story is the factory tested dual exhaust and found the single gave more HP. Many will remember the 1970's 4 cyl motorcycles which had individual exhaust pipes. Cycle magazines were full of ads for "4 into 1 exhaust, 20% more power". Finally, Honda and others shipped w/ "4 into 1" exhaust and the same companies didn't skip a beat advertising "4 separate pipes, 20% more power".
 
"you can only run headers with this intake. "

there are several different versions of Clifford slant six intakes, the one shown in the photos above has a heat stove on the bottom side that should mate to a stock
slant six exhaust manifold.
The Slant Clifford Intake that I run has a hot water chamber on the bottom side, (its not water cooled, it is water heated) and has nitrous bosses at the runner flanges.
I machined the bosses to accept injectors and run MPFI, with that I have the hot water chamber not plumbed.
 
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my68barracuda said:
"you can only run headers with this intake. "

there are several different versions of Clifford slant six intakes, the one shown in the photos above has a heat stove on the bottom side that should mate to a stock
slant six exhaust manifold.
The Slant Clifford Intake that I run has a hot water chamber on the bottom side, (its not water cooled, it is water heated) and has nitrous bosses at the runner flanges.
I machined the bosses to accept injectors and run MPFI, with that I have the hot water chamber not plumbed.
Click to expand...
John, I'm pretty sure my68barracuda is correct about headers only. That is a real early Clifford manifold (can tell by the ribs in the plenum), but it has no bolt holes to connect the intake and exhaust, even though it does have the heat stove. I can't say for sure as I have never tried it. I know the later Clifford manifolds must use headers.
 
I have the exact same manifold (ribs and all). It has places on it that can be drilled out for bolts to connect it to the factory exhaust manifold. Mine is on a race motor so that proved unnecessary (headers).
 
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