Offenhauser manifold question

Picked this manifold up a while back, thought it was pretty interesting Thinking of putting it on a 327 with a Carter AFB #9652SA 650cfm carb. This is going in my Model A Sedan with a 700R4 and a 9" with 3.73 gears. Saw an advertisement on the back of a 1975 Rodaction mag calling it a "Dual Port 360". Would this set-up give good gas mileage as I am going to drive the wheels off of it?
Any thoughts or experiences with this manifold would be appreciated.

 

I would try it

I had one back " IN THE DAY " and it was designed for low to mid range torque ( if I remember correctly ). I had it on a 327 SBC ... in a 55 Cameo pickup. It works well ... at lower RPMS and made good torque. Your rear end ratio with a 700R4 and a 3.73 gear ... ( 30 % overdrive ) will be about 2.61 in high gear. Depending on your rear tire size ... the 327 should turn around 2,000 RPM @ 70 ... so the low end power and torgue at reduced RPMS should be GREAT

 

Thanks Deuce.
Was thinking of putting a factory grind 350hp cam in it also.

 

I had one on a 360 Dodge. Less power, no more mileage than a stock 4bbl. Chucked it.

 

Had one on a 428 FE worked good

 

I sold a fair amount of these "back in the day" when they came out in the 70's the idea was to gain mileage,reduce emissions.There are two versions of this intake square-bore and spread-bore the basic principle works a little better with the spread-bore because of the small primaries and large secondaries.Your square bore can be made to work well also,but you will need to do some tuning that works with the manifolds design.To learn more about this intake click on "The Alliance" at the top then in the far right column click on vendors,then scroll down to Exeter Auto and you can click on:Offenhauser Catalog to learn more.The tuning I talked about will usually involve a leaner primary jetting because of the intakes Hi-Velocity primary runners.I also suggest with your combination and 327/350 HP cam that you run a 2400-2600 stall converter.

 

I was using a 327/300 HP factory camshaft but a 327/350 might work well.

 

A 300hp cam was my first thought. I have had the motor for 20 yrs. and it is supposed to be rebuilt. but won't know till I open it up. I have never built a motor, always took the easy route with crate motors, but I really like 327,s. Had one in a '65 El Camino yrs. back and loved it.

 

With that intake the L-79 327/350HP will be a better choice for a cam the transition from primary to secondary flow in the Dual-Port will come in at about the same RPM as the cam begins peak torque which is also the reason I recommended the torque converter stall in my above post.I have used this combo in two of my own previous builds,when it all comes together you will "feel the kick" for all around cruise the MPG will be good once you get the primary jetting and timing in syc.

 

That was my first new intake! I had it on a 331 small-block Chevy topped with a Carter AFB. The motor was 9.5 to 1, with a viking 100H cam and 462 heads with an accel distributor backed by a Niel Nilson power-glide. It ran great and got about 23 mpg in a 65 box Nova. It also ran in my 406 small block, with a comp 280 cam with Rhoads lifters, 862 heads with a lot of porting done, 10 to 1, MSD, backed by a wide-ratio Muncie M21 in a 57 Chevy Sedan Delivery, weight 3024 lbs. I got 24 Miles to the gallon in that...if I kept my foot out

 

Thanks for your input Duece,JeffB2, and thebigdaddyo, I feel more confident about my decision to use this manifold. One more thing. I want to get the heater hose fitting out of the manifold. Been told that if I heat it up and spray WD-40 at the base of it this will make it easier to remove? Was also going to weld a nut to the top of it to make it easier to remove.

 

Here is a link regarding the Dual-Port Manifold design. Understanding why the manifold was designed and what it's intended purpose is will help you decide if it is the best manifold for your engine. When my Grandfather designed the Dual-Port manifold, he was experimenting with variable induction systems for carbureted applications. The Dual-Port was the production result of these tests.

http://www.jalopyjournal.com/forum/showthread.php?t=123509

Dan Marvin, Owner
Exeter Auto Supply

 

Isnt that about the last manifold offy cast up??

 

Thats one way of removing the fitting. I have also had good luck with building a little dam around a fitting and using some CLR and let it soak.

 

Bigdaddyo What is CLR?

 

CLR is a Brand name for a calcium, lime, rust remover. Mostly used for bathroom build-up, but does helpsomtimes on rust and the white crap that builds up on fittings.

 

Thanks bigdaddyo, thought that might be whay it was but I had to ask.