[blykins]

That is a VERY mild lobe in both terms of lobe aggression and duration. A 520 inch engine would need about 20 degrees more duration.

Here's another engine builder tip:

Be very cautious when using components straight off the catalog pages. When writing these catalogs, the writers have no knowledge of what displacement your engine is, how much your heads flow, what valves are in your cylinder heads, if the spring pockets have been cut, etc. A valve spring that's recommended may work just fine on one head, but if another head has different valve lengths, spring pockets have been cut, etc., the spring pressures will just not be correct.

It's best to take some measurements on your own, act as though the descriptions are not even there, and use the numbers to make the selections.