360 or 340 ??????

360. The longer stroke simply makes more torque...that makes for a more friendly street driver. Really easy to make serious power with. I do love a 340 but dollar for dollar, 360 is the bang for the buck motor to build. Cheaper pistons to!!

Since you are doing a rebuild anyways, what some engines come with stock is a moot point.

The 408 is simply a beast. A friend has one in a '74 Duster and it makes torque everywhere. I'd reccomend it if you got the coin.

Oh...on those W2 heads, that is great option if you have plenty of $$$$.