Is there really a difference..??

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nodemon

nodemon

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1971 318 .040 over
LD4B vs PERFORMER RPM..
What's your preference, and why..?
Is there really that much of a difference..?
I have one of each.. I'm going to run one and sell the other.
 
The RPM has 340/360 port size, the LD4B has 318 port size. Just one thing to keep in mind.
 
LD4B is an aluminum version of the stock intake manifold. I wasn't sure about the port size.
 
LocuMob said:
LD4B is an aluminum version of the stock intake manifold. I wasn't sure about the port size.
Click to expand...
I don't think that's right. The LD4B is to the 318 what the LD340 is to the 340/360. It's a pretty stout small port dual plane intake. The regular Performer is closer to a stock intake than the LD4B is.
 
LocuMob said:
LD4B is an aluminum version of the stock intake manifold. I wasn't sure about the port size.
Click to expand...
it absolutely is not an al-loo-mini-mum version of a stock intake. the plenum and runners are noticeably larger and different. it does, however, retain the stock 273/318 port size.

source: i have a LD4B on my motor and i have a stock 318 4V manifold and compared them side by side.
 
RustyRatRod said:
I don't think that's right. The LD4B is to the 318 what the LD340 is to the 340/360. It's a pretty stout small port dual plane intake. The regular Performer is closer to a stock intake than the LD4B is.
Click to expand...

junkyardhero said:
it absolutely is not an al-loo-mini-mum version of a stock intake. the plenum and runners are noticeably larger and different. it does, however, retain the stock 273/318 port size.

source: i have a LD4B on my motor and i have a stock 318 4V manifold and compared them side by side.
Click to expand...
Yep, I was wrong. It's been a minute since I dealt with SB intakes and got them mixed up. I meant to say what Rob said.
 
nodemon said:
1971 318 .040 over
LD4B vs PERFORMER RPM..
What's your preference, and why..?
Is there really that much of a difference..?
I have one of each.. I'm going to run one and sell the other.
Click to expand...
i doubt you'll notice a gnats *** difference betwixt the two.

if running the RPM, i'd probably gasket match the heads if i was feelin' frisky.

LD doesn't have a provision to mount the coil or any AC, the RPM has a coil provision but same deal with AC (if any of that matters to ya)
 
LocuMob said:
Yep, I was wrong. It's been a minute since I dealt with SB intakes and got them mixed up. I meant to say what Rob said.
Click to expand...
No biggie. I don't know which way is up most of the time.
 
If your using the 318 heads use the LD4B. Much better fit . Take a straight edge and spit the intake runners up the middle and continue the center of the port to the top of the intake so it can be seen when laying on the engine.

After installing the intake bolts loose. Then align these marks with the center of each valve cover bolt hole in the head which is the center of the head port.

With the china wall pins installed once you have the intake at its best alignment tap down on the ends of the intake.

This will put marks where the intake is at for best alignment. Drill the intake for these pins . This will hold the intake where it will be fitted and work the best.

Why they don't come drilled? Is not that they were missed .

Many remove the pins or drill big holes we don't do that here. Just an FYI use it or not I thought I would mention what I have been doing since the 70's. If the holes were drilled for a different engine have them filled either with weld or a press fit slug of aluminum.
 
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