Stop in for a cup of coffee

360DartGT66 said

The ports on the LD340 are taller to match the intake ports on the 340 (and up) cylinder heads.
Also, the runners from the upper and lower planes go to different intake ports, they are swapped. I have no idea if that makes any difference, I would guess not. Unless that change made it possible to make the runners a little longer.
And the plenum is larger on the 340.

Click to expand...

Chrysler engineering is notorious for optimizing runner length. On the Modern 5.7L and 6.4L engines they use active intakes that switch between short and long length to optimize either HP or TQ at different RPM. (long for TQ, short for HP)

They may have swapped sides to get longer length and more TQ.