Best Intake Manifolds For A '273 or 318'

[69 Cuda 440]

What is the general overview......

On the 273,

The 'Edelbrock' #LD4B ~ Dual-Plane High-Rise has always been regarded as the
'staple' for the little 273.

 

[krazykuda]

The Edelbrock LD4B or SP2P for low end torque and mid range power.

 

[roccodart440]

THat looks like a perf RPm which is hard to beat for al around use.

 

[mischiefdart]

I have an edelbrock performer 318/360 on a cammed low compression 318 and it runs great. The cross section of the ports is a little smaller than the ld4b so velocity is a bit higher on the smaller engine.

 

[krazykuda]

THat looks like a perf RPm which is hard to beat for al around use.

You can see the LD4B cast in the manifold in the picture if you look closely.

Yes, they are similiar to the performer, but I feel that they run better.

 

[69 Cuda 440]

With the 'Small Port' Cylinder Heads {#2658920 or #2843675}

The 'Edelbrock' #LD4B always worked best on our Applications.

Manifold Port Size = 1.05" Width x 1.955" Height

 

[krazykuda]

The problem with the LD4B is that it doesn't have mounting bosses for the coil like the stock OEM manifold. You have to find a place to mount the coil.

 

[bad440]

It suite looks like a good intake....the perfformer is pretty good.but it has to have to a bunch of water plugs on it because it's for so many different applications....

 

[teringer]

ld4b is the best one for hp up to 7000 rpms

 

[krazykuda]

ld4b is the best one for hp up to 7000 rpms

Yes, and the SP2P is good up to about 5000. Lots-o-torque in low and mid range. Great for trucks, tow vehicles and daily drivers.... Low end grunt.

If you want to wind it higher, then the LD4B is the way to go.

 

[69 Cuda 440]

Can't beat the Edelbrock LD4B in the,

2500 to 6500 RPM Range = Wide Power Range

 

[JBurch]

Another choice not mentioned would be the Holley Street Dominator.

 

[69 Cuda 440]

The early Offenhauser {pre-1970},

A very tall Aluminum Dual-Plane High-Rise Intake with narrow Port Runners.

Good for 3000 to 6800 RPM's

 

[71beater]

Gotta D4B on a hot little 70's 318, pulls well past 6K... I don't know if there's any difference from the LD4B besides the drilling.
(Yes I know the drilling is for early 273, it might have early 273 heads, I've never dug into it to see, but the bolt heads do sit flat without it having been spot-faced or anything. The compression says it may... 170 psi cranking...).

 

[krazykuda]

The early Offenhauser {pre-1970},

A very tall Aluminum Dual-Plane High-Rise Intake with narrow Port Runners.

Good for 3000 to 6800 RPM's

That one has too high of a power band for his cam. The LD4B is the best choice so far.

 

[69 Cuda 440]

The LB-Marine Intake

Cast Iron, and cast with an Open-Plenum and smoothed Runner-Ports.

Very good for Low-End Torque and Mid-Range Power {Range 2400 to 5600 RPM's}

 

[mischiefdart]

That marine intake looks a lot like a 273 commando unit. I have an SP2P on my '68 D100 and I'm not impressed. I hear they work good with a stock or very small cam. The 318 in my truck falls flat on its face just past midrange. I did not build the motor (came in the truck) and have no idea what is in it or how well it was built.

 

[69 Cuda 440]

1966 - 1967 ~ 273/235 HP ~ 'Factory Stock" ~ Cast Iron Intake Manifold

Designed for Carter AFB Carburetors {1 7/16" Primary x 1 9/16" Secondary}

Low-Rise - Single-Plane - 4-Bore Hole Mounting Area

Designed for Low-End Torque with the Low-Plane Design, and Mid-Range Power with the shorter Runner Ports.

Range = 1800 to 5200 RPM's

 

[69 Cuda 440]

Reg,

The 'Weiand' Dual-Plane Intakes..........

Runner Port Sizes...... 1.00" Width x 1.96" Height

Power Band = 0 to 6000 RPM's

Performance = Street

 

[lilredridinghoo]

what about using an LD340 on a 273 or 318 ?

 

[69 Cuda 440]

what about using an LD340 on a 273 or 318 ?

Edelbrock #LD340......................................Edelbrock #LD4B

Port Size... 1.16" Wide x 2.27" Height............. 1.05" Wide x 1.955" Height

 

[rumblefish360]

You can see the LD4B cast in the manifold in the picture if you look closely.

Yes, they are similiar to the performer, but I feel that they run better.

I like it on a more aggressive build. The Performer is fine though.
The Weiand offering are good choices as well.
The Edelbrock SP2P was an intake designed for higher mileage during the gas crisis in the 70's. Use it to seek mileage and you'll be rewarded with such.

I've never run any of the Offenhausers.

 

[69 Cuda 440]

Rumblefish,

On the Offenhauser.

With a stock Carter AFB 500 CFM. The Offenhauser offered 'no real gain' on a 273 Commando.

But, the Offenhauser 'worked well' with the Holley #1850 ~ 600 CFM #4160 Series {1 9/16" x 1 9/16"}

 

[AJ/FormS]

I have had a lot of fun with just a Thermoquad and matching smallport iron intake.