Which exhaust manifold for a 72 Dart???

[JGWoodman]

I have switched out from a /6 to a 318 into a 72 Dart using all stock parts, including k-frame. The donor motor turned out to be junk so I purchased a rebuild from a local shop but now the drivers side exhaust doesn't sit right. It hits the block at the down tube/two center ports leaving a 1/8 in gap on the bottom side. The block is a 78 - manifolds are the oraginal 72's.
Question #1: can I grind the high spot down on the block where it hits without doing damage? The block has DROPS for a lack of better description- where it had smog??? hookups that have now been pluged.
Question #2: which models can I find a proper fit exhaust from? the interchange book does not have 78 block and manifolds listed.

Any help would be apprecated.

[340duster1]

I am going to assume the manifold is hitting the boss for the air pump ports on the cylinder head. I had this same problem on a duster years ago and my cure was to replace the heads. I would suggest two solutions. Find an exhaust manifold from a 75 or 76 A-body.This should cure the problem. Or consider grinding the spot down on the head (be careful with this one)