So I am new to the W2 and have been trying to read as much as I can find. I got a set of 48⁰ W2s for a great deal. I see they can be made to work on the standard 59⁰ blocks.
There were a couple of items mentioned above about the differences between 48 degree tappet angle W2's and the W2's for 59 degree tappet angle blocks. Those differences mentioned above are notches in the intake face for pushrod clearance due to the change in pushrod angle, heads casted after Jan 10, 2002 will need pushrod oiling and T&D rockers & the heads will not have the shaft oiling hold drilled in the head deck through to the pedestal.
One other difference that 48 degree W2 heads have is a 15 degree valve angle which differs from the stock 18 degree valve angle. You can get pistons made with 15 degree valve pockets or if using 18 degree pistons, like most off the shelf pistons are, then piston to valve clearance becomes more tricky. If you need more piston to valve clearance with 18 degree pistons, you can fly cut the pistons or angle mill the heads. Angle milling the heads will create the need for other intake or head mating modifications and and exhaust complications depending on your vehicle being used.