i was wondering if the heads off of the 318 l.a. engines would work on the new318 magnums

 

Yes, they will bolt right up to the block. However, you will have to change the exhaust manifiolds and I believe the intake manifold as well.

 

Why on earth would you want to? The Magnum heads are a much better design. The intake manifold bolts are at a different angle, so you'd have to drill the correct ones in your manifold. The exhaust manifolds didn't change to the best of my knowledge. The gaskets looked the same when I threw headers on my Dakota. Magnum valvetrain is oiled through the pushrods and LA valvetrain is oiled through passages in the heads, so you'll need to verify that the hollow pushrods are oiling the LA valvetrain properly.

Again why do you want to do this?? Get a set of Magnum HD cast iron heads - they flow better than even the R/T heads and iirc they're cheaper.