Manifold help

I have a 318, I just took the old stock manifold off because I had a torker 340 manifold to put on. well It doesn't seem to fit. will that manifold only work with 340 heads on the 318?

Also it has a small dowel on the engine block that the old manifold has a hole for. And at each corner there are these little tiny tabs that are sticking out? they are very thin easily bent little things, two each at all for corners. Are those part of the head gasket? Do I leave tose when instaling the new manifold?

If I'm limited to only a manifold that fits 318 heads to add a 4 barrel, what manifold should i be looking for?

Any help on the things I pointed out would be great. . the car was running this afternoon, and now its sitting with no hope of starting up till i figure something out.

I Have AC and want to keep that, if that helps the suggestions for certain manifold.

Thanks for any help