LD4B or LD340

[68 Sedan]

Not that I'm ready for it, but I'm getting closer to deciding what intake I want to run. So can anyone tell me the performance difference between the LD4B and LD340? I know they are made differently, but what's the deal?

 

[thestover]

The LD 340 was basically the factory early 340 intake only in aluminum I have one on my fresh rebuilt 340 running factory exhaust manifolds. Ive been told that the new elelbrock air gap is the one you want especially with headers. Not sure about the LD4B. Correct me if Im wrong.

 

[GTXperience]

I believe the LD4B was meant for the smaller port/valved LAs vs the LD340 (as thestover mentioned) being for the larger port/valved 340s/360s (especially if the 360s were opened up to 2.02s instead of the 1.88s).

 

[C130 Chief]

The LD4B had smaller runners to match 273/318 heads (D4B was similar with pre-66 bolt angle). LD340 had larger runners for the 340/360 heads. Much like the Performer/Performer of RPM today. All are good intakes for their intended purpose (not that the factory iron intake was at all bad).

I'm using an LD4B on my 318 build for 2 reasons. First I have one gathering dust, and second I will absolutely not suffer the sideways-a$$ed thermostat of a Performer. I'm also only building a 300 HP street engine. If I was building a 340/360 or more than a 300 HP 318 I wouldn't screw around with small port heads and would probably just get myself an RPM.

Really 300 HP is about all small runner heads support. Beyond that, you'll be much happier with the bigger heads and intake, all else (compression, carb and exhaust) being equal. If you plan on going much beyond 400 HP, consider a single plane.

 

[rumblefish360]

The LD 340 was basically the factory early 340 intake only in aluminum I have one on my fresh rebuilt 340 running factory exhaust manifolds. Ive been told that the new elelbrock air gap is the one you want especially with headers. Not sure about the LD4B. Correct me if Im wrong.

The LD-340 is a high rise dual plane intake designed for the 340 - 360 and larger engines. It is not for a 318 unless it is really pumped up. And that is debateable. It is not a simple or basic rework of the factory iron intake.
It is taller with easier, nicer & larger flowing runners.

The Edel. RPM and Air-Gap version have the same performance showings and only differ down the road when the engine has been running for a while. The runners stay cooler when in operation on the air gap vs the RPM which has the heat passage. The heat passage in the RPM makes it an excellent dual purpose intake for all seasons.

LD-349 vs RPM. According to those whom have tested them both, theres no real difference between them and say not to bother with a swap to the RPM. No meaningful power was found between them, according to them.
(I'd love to waste the money myself and find out.)
Some have claimed they called up Edelbrock and spoke with tech which told them, Dont bother with a change.

On the LD4B, what C130 Chief said. I also run one on my 318.

Somewhere in this place I posted pictures with measurements hieghts of the intakes;
Stock 4bbl, LD4B, LD-340, RPM Air-Gap.

 

[68 Sedan]

Thanks for the info! I figured the LD340 was (basically) an aluminum version of the factory 340 intake, much like the DP4B was (basically) an aluminum version of the 70 383 intake from cars originally equipped with a Holley carb. But I didn't know about the differences in the runner sizes. The LD4B is an odd looking thing compared to the stock or LD340 intake.

Since I'm basically going for a mile cruiser type build, it sounds like a LD4B might be the best choice.

 

[crackedback]

The LD340 isn't a copy of the factory iron intake. Not even close IMO. If you set them next to each other, IIRC, the iron intake with a 3/4" spacer is closer in height to an LD340.

If you have an LD340, RPM or Air Gap, run it and don't waste your money on buying any of the other two to test them out. It won't make a significant difference and is a waste of money.

LD4B is a great intake as well for the smaller port engines. I really like them on the late 360's as well.

 

[68 Sedan]

Well, the DP4B isn't an "exact copy" of the 70 383 intake either. But if you look at them, the layout of the runners and basic design of the intakes is the same. BUT, the aluminum versions have larger runners for better breathing. That was my point in saying they were "copies". They are basically the same thing as the original iron intakes, only better

 

[Longgone]

I`ve read where the LD340 was developed for Nascar and is based on the early 340 intakes but with the added performance, not to mention probably 15 lbs. lighter. Some will even have Chrysler part #`s since all stock car pieces had to be made available to the public. As the guys mentioned earlier the LD4B is a performance intake for the smaller port 273/318 engines. Both are good performance intakes but have been superseded by newer models like the Performer.

 

[cavemanmoron]

What engine are you using and what rear gears, and cam??

I am using a LD4B, on my 318. Awesome for my setup.

318, stock bore, the block cleaned up very nice,
# 302 heads, stock valves size, cut .005-.007 to clean up,
stock 2.93 sure grip 7.25 rear,
Mopar .430/.450 cam,
Edelbrock 1406 600 cfm electric choke carb,
duals off the stock exhaust manifolds.

http://www.youtube.com/watch?v=Ud8mci4rjFU

 

[68 Sedan]

Sounds really good at idle, but also sounds like your exhaust doesn't have enough backpressure when you gun the motor.

I'll be running a (basically) stock 318. At this point I'm planning on a VooDoo "401" Advertised Duration 256/ 262, Lift .454/ .475, upgraded valve springs (haven't decided on which ones yet), possibly going from the 1.50 to 1.60 exhaust valves, headers, O.E. Mopar 600cfm Holley, O.D. 4 speed and (for the moment) 3.23 rear.

The OD will allow for something a bit steeper later on. Also, I was originally planning on running a Prestolite which when set up properly are about as good as anything else. But all the talk of "building for MPG" has me second guessing that. Maybe sneak a Petronix in the Prestolite housing, maybe run a Jacobs (ran one on my Bee and loved it). I don't think I'll bother with something like a 6A or 6AL cause they only multi-fire at (relatively) low RPMs and will be of little help on the highway. It will retain the P/S and A/C.

Speaking of my old Bee, I was running a Jacobs on it (don't remember which box but am sure that one isn't available any more) along with their stock looking fast saturation coil, 7mm Taylor wires, Champion J-11Y gapped to .045", 9.9:1, DP4B, OE 625 AVS tweaked, MP electronic distributor, Hemi grind cam (the later .474/280 ) ProStock 1202 headers, 2.5" all out with Walker Super Hemi Turbos, stock converter, B&M shift improver, and 3.91:1
Twisting it about 3400 I was getting 15mpg and it ran a best of [email protected]

 

[cavemanmoron]

Sounds really good at idle, but also sounds like your exhaust doesn't have enough backpressure when you gun the motor.

There is no "H" or "X" balance tube, so thats why the
"Blatty" sound when hitting the gas.

A balance tube was used by Mopar on Big Block cars mostly,
so thats why I didn't bother with one, but if you buy a
"Flowmaster" kit they come with an exhaust balance tube "H" pipe.

I noticed a lot different sound on my old Chevy van when I had
an "H" pipe added to the dual exhaust, back in 1984.

Lee/cavemanmoron
K2HAT Amateur License call sign, {if your a "Ham" you will know what I mean.

Sounds really good at idle, but also sounds like your exhaust doesn't have enough backpressure when you gun the motor.

I'll be running a (basically) stock 318. At this point I'm planning on a VooDoo "401" Advertised Duration 256/ 262, Lift .454/ .475, upgraded valve springs (haven't decided on which ones yet), possibly going from the 1.50 to 1.60 exhaust valves, headers, O.E. Mopar 600cfm Holley, O.D. 4 speed and (for the moment) 3.23 rear.

The OD will allow for something a bit steeper later on. Also, I was originally planning on running a Prestolite which when set up properly are about as good as anything else. But all the talk of "building for MPG" has me second guessing that. Maybe sneak a Petronix in the Prestolite housing, maybe run a Jacobs (ran one on my Bee and loved it). I don't think I'll bother with something like a 6A or 6AL cause they only multi-fire at (relatively) low RPMs and will be of little help on the highway. It will retain the P/S and A/C.

Speaking of my old Bee, I was running a Jacobs on it (don't remember which box but am sure that one isn't available any more) along with their stock looking fast saturation coil, 7mm Taylor wires, Champion J-11Y gapped to .045", 9.9:1, DP4B, OE 625 AVS tweaked, MP electronic distributor, Hemi grind cam (the later .474/280 ) ProStock 1202 headers, 2.5" all out with Walker Super Hemi Turbos, stock converter, B&M shift improver, and 3.91:1
Twisting it about 3400 I was getting 15mpg and it ran a best of [email protected]

 

[AdamR]

I wouldnt say the LD340 is an aluminum version of the factory intake. Its should make all most as much power as a RPM or air gap. LD4B is a 318 port size version of the LD340.

 

[440SCOUT]

The LD340 isn't a copy of the factory iron intake. Not even close IMO. If you set them next to each other, IIRC, the iron intake with a 3/4" spacer is closer in height to an LD340.

If you have an LD340, RPM or Air Gap, run it and don't waste your money on buying any of the other two to test them out. It won't make a significant difference and is a waste of money.

LD4B is a great intake as well for the smaller port engines. I really like them on the late 360's as well.

I AGREE!
that ld340b i have is taller than the stock manifold ...