Manifold help

Thanks for that info guys. So that manifold "should" physically fit on there? even if the port size is too big. I felt like it was too "wide" to sit down in there properly, like it was just the wrong manifold. It didn't seem like the dowel was the factor keeping it from fitting, If I pull the dowel out just to see if that was possibly the difference, will it hurt anything to not have the dowel on there, if i put the stock manifold back?

Thanks also for the info on the little tabs and the dowel,

If I could find a really good deal on a 273/318 manifold i might get one, but this manifold was a freebie, and should only be on there till i get a set of heads and a few other items i need to put the 340 in it. . .

Thanks for the replies