Total Timing?

Timing is very individualistic. Without knowing the cam or compression I would say the best thing you can do is vary it 2° at a time and see what it likes.

That being said, as it's a 340 with factory heads, I'd think it will want closer to 38-40° total, but I dont think it should all be initial. The engine won't need that much at lower rpms... So make sure you have the right springs in the distributor. The curve is more than just initial and total.