W8 heads are excellent; but, they are not designed to be used "out of the box". They are designed to be used as the basis for CNC port work. The same is true for the intake manifold.
After port work is done, the heads can and will flow close to 370CFM @.700"@28". And, you can ADAPT them to a 59 degree block BUT they are designed to mount on a 48 degree block.
Since they are designed as a pure race head, they use pure race rockers(Jesel or T&D). And they oil through the pushrods(AMC solid lifters or special roller lifters).
If you are on a budget, use the W5s. Properly ported, they can flow close to 325CFM@.700" @28". They use standard type shaft rockers, etc. and fit a 59 degree block.
You give up over 100HP and 700RPM by using the W5s but it is a much less expensive setup.
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