8The LD4B and LD340 are very different intakes. If you want an LD4B for your 318 project look no further than the Weiand Stealth, its pretty much an exact copy of the 4B.

The iron manifold is most likely valuable only to a restorer or a racer needing a factory iron manifold for a specific class. If you are want to put it on a 318 you should gasket match the heads or run 340/360 heads or else you'll have port mismatch in a direction that will affect performance.