offy 360

[Omie01]

Any body here ever use an Offenhauser 360 Dual plenum "Equa-flow"? The only thing I can find is that it has a performance range of 1800-8800rpm. Looks like it will work with ram-air though. Note: Not the dual port model.

 

[ScooterDog]

I'm certainly no expert, but everything I've read says that Offy was a dud. The stock cast iron manifold was better I guess.

 

[MotoArts]

No other manifold is designed like it.

For a good reason.

You can't get (real) dual plane style 1500 RPM torque and tunnel ram HP out of any intake...

 

[kidwithfastback=fast]

I had one , never ran it. It was big as a barn inside, but all my research results were similar. Too big, no bottom at all, and was regarded as the bottom pick of the the many options for the Cleveland. Sold it for 100$ on eBay.

Kole

 

[Mesozoic]

I had one and found that it had no low end torque production with an off the shelf Comp Cams 280 Magnum hydraulic flat tappet cam. Midrange and top end, on the otherhand, was a different story. It's just older technology - a better option would be an Edelbrock Torker for more high RPM work.

 

[jbojo]

I had one and found that it had no low end torque production with an off the shelf Comp Cams 280 Magnum hydraulic flat tappet cam. Midrange and top end, on the otherhand, was a different story. It's just older technology - a better option would be an Edelbrock Torker for more high RPM work.

Omar,

The Offenhauser is not too good from what I read about it and the Torker is a good high rpm manifold but I don't believe that the Ram Air will fit with the Torker. Are you building your new motor for the strip or both street/strip? If for both I would go for the Blue thunder manifold as it was designed after the Boss manifold. I am using this manifold and some forums said the Ram Air will not fit but mine fit just fine. It has a good low end and good top end and runs just fine. It's slightly over $400.00 and are hard to find used. Blue Thunder now also has a 351 CJ manifold that is optimized for more HP but is around $600.00. I didn't see this manifold when I initially bought mine. I think that our motors will be pretty similar and I am happy with the performance of this manifold and has more power than I need.

 

[Mister 4x4]

Edelbrock Performer 2750 (Dual Plane) for 351C-2V, or Performer 2665(Dual Plane) for 351C-4V, are pretty much your best solutions for fitting with factory Ram Air.

There are others: Weiand, TrickFlow, et al, but the only ones anybody has used with their factory Ram Air without modification (that I'm aware of) are the Edelbrock Performer Dual Plane intakes.

Hope that helps.

 

[jbojo]

Edelbrock Performer 2750 (Dual Plane) for 351C-2V, or Performer 2665(Dual Plane) for 351C-4V, are pretty much your best solutions for fitting with factory Ram Air.

There are others: Weiand, TrickFlow, et al, but the only ones anybody has used with their factory Ram Air without modification (that I'm aware of) are the Edelbrock Performer Dual Plane intakes.

Hope that helps.

The only mod that I had to do was with the air cleaner base and that was because I was using the taller MSD distributor. If I had used a stock height distributor no mods would have been needed. Not sure about the Blue Thunder 351C 4V CJ version though. I think Omar is trying to build a high RPM/HP motor in addition to the one currently in his car.

 

[Mister 4x4]

It's going to be cool, from the sounds of it. I just remember spending lots of time researching to find the best things to boost the performance and still all fit under the Ram Air system without having to chop it up.

I like how yours came out - you can't even really tell anything's been done - which is what I would've tried to do had I not gone with the Duraspark/stock dizzy set-up in mine. After having to cut and repair so much on my car, I didn't want to start-in on modifying repop "factory cool stuff" (since my car's original Ram Air air cleaner was missing when I bought it).

 

[Omie01]

I'm building a street motor, that I want track style performance out of. I'm trying to build a car that will handle corners, take off and brake well. I don't usually get into street races but will from time to time play with someone on the street. Even with 350 hp most newer cars are still faster than my old mustang, so I'm trying to build something that would keep up with a few of todays sports cars. Yes, I know its apples to oranges but a well built Cleveland should hold its own on the road. I broke down and bought an RPM air gap, I'm gonna give that a shot first as I can't seem to get my hands on a Blue Thunder intake, I called around and everybody has a waiting list on them, and the last guy I talked to was a dick about my inquiry.

 

[Mesozoic]

EFI is a pretty nice boost in performance if you're a keener.

 

[jbojo]

I'm building a street motor, that I want track style performance out of. I'm trying to build a car that will handle corners, take off and brake well. I don't usually get into street races but will from time to time play with someone on the street. Even with 350 hp most newer cars are still faster than my old mustang, so I'm trying to build something that would keep up with a few of todays sports cars. Yes, I know its apples to oranges but a well built Cleveland should hold its own on the road. I broke down and bought an RPM air gap, I'm gonna give that a shot first as I can't seem to get my hands on a Blue Thunder intake, I called around and everybody has a waiting list on them, and the last guy I talked to was a dick about my inquiry.

Are you still planning to use Ram Air? I think that you will have height issues with the Air Gap manifold. If you do it will be interesting to see if you can make it fit with the Ram Air system.

 

[Mister 4x4]

I broke down and bought an RPM air gap

Good luck - I'd always heard the RPM Air Gap is awesome, but won't fit with factory Ram Air.

 

[Omie01]

I will not be using the Ram Air air cleaner, I'm going to leave the plenum in the hood, I found an aftermarket air cleaner that will sit up in the plenum so when the flappers open the air filter element will be surrounded by cool, fresh air! That will have to be good enough as I don't want to modify any of my stuff to make it work. The air cleaner will look cool hanging on my garage wall!!lollerz

 

[barnett468]

.

a performer rpm will give you just about as much power and it is shorter.

you can also run a blue thunder or a stock boss 351 intake.

blue thunder . . send it out to get the runner flow equalized for $150.00 and it will spank.

boss 351

or one of these

 

[Omie01]

All these options are a no go at $500 plus, BT, $455+$150 for runner matching? Boss/Shelby intakes are hovering around $700 and most of them are spreadbore so I would have to run an adapter. I have a performer now and all my research says that the Air Gap will give me at least an extra 1000 rpms. The cam I got is rated from 1800-6200 rpms, Edelbrock states that the performer is good to 5600rpms, and the Air Gap will take me to 6500rpms. I was thinking about port matching my performer but there is no solid info that this is a benefit. If I'm not happy with any of these I may go back to a standard square bore 4v iron intake as I know they are capable of the 6200rpm if everything is tuned right. Funny thing is, the Air Gap is a heavy intake for aluminum, and I think the iron intake is only a little heavier than it. I really wish someone would build a low plane/ dual plenum intake with enough restriction for bottom/mid torque but flares out to match a factory 4v head, and make it mildly affordable/available. These days all we see are intakes made for aluminum heads, all out drag racing intakes, or over priced "Stock" style stuff. Even my engine builder told me he would port match the Air gap, not sure why though, I thought the smaller ports are what make better torque down low, and if its capable of 6500 rpm what would it benefit?

 

[Don C]

You might want to check out this dyno test with various manifolds on a small block (360) Mopar. Tests 1 & 2 are the Performer and RPM Air Gap. The Air Gap gives away a little torque at 3,000 but catches up and passes the Performer quickly. The Performer doesn't drop as much as you would think above 5,500.

http://www.hotrod.com/how-to/engine/mopp-0108-dyno-testing-small-block-intakes/

 

[Mister 4x4]

I will not be using the Ram Air air cleaner, I'm going to leave the plenum in the hood, I found an aftermarket air cleaner that will sit up in the plenum so when the flappers open the air filter element will be surrounded by cool, fresh air! That will have to be good enough as I don't want to modify any of my stuff to make it work. The air cleaner will look cool hanging on my garage wall!!lollerz

That's pretty much what I have right now - I've been too lazy to paint the Ram Air air cleaner. It's basically just a chrome Edelbrock air cleaner, a little bigger than the center section lid, but still fits in the hole.

 

[barnett468]

.

ok, i see they do not make a performer rpm...bummer because there is only maybe a 7 hp difference between that and the air gap . . both those will have a LOT more power than a plain performer on a 6000 rpm engine.

the blue thunder works well just the way it is but for racing apps like yours, i would fix the runners . . if you do that, it will outperform the air gap, plus your air cleaner will fit.