A few comments
1 - If the engine won't see a ton of miles, you may be able to save some dough and lose all worries of fitting a set if you just cut for bigger valves, as opposed to adding hardened seats. Those heads don't really have hardened seats, they have seats that were induction (I think that's the right term) hardened, think of it as surface prep. When he cuts for new seats, it'll go away
2 - Adding just the valves won't help flow, you'll need to work on the bowls to take advantage of a better valve. The D2s don't flow well, (220-ish CFM) but can hit 280 or so and support over 500 hp with port work and CJ valves
3 - Be sure those heads match the headers you plan to run. Manifolds are less of an issue
I have had good success on budget motors with Alex's parts valves. They sell a nice CJ valve, likely offshore made, but a decent piece, also some decent street valve springs for the money
https://www.alexsparts.com/ss-valves-fe-ford-cj-w-2-090-1-650-high-performance-428/However, in the bigger power motors / high spring pressure, I prefer a Ferrea, but you'll pay more
Last thing, just to sort of clear up the potential of these heads
- The port location is a med riser centerline more or less, but they are not MR ports. They flow far less and are smaller in every dimension. However, we were able to port my last set more or less to MR shape and dimensions using measurements from a silicone mold, more importantly, my current set outflows an unported med riser by a significant amount, so they can do well
- Yes they are almost identical to C8AE-H, but C8AE-H heads are equally poor for performance without additional work, but of course, with work, they do pretty well and are real cheap. I wouldn't say they run with the best of them but they can do great. They peak about 280 cfm with a good street port job, which is great, but the exhaust doesn't keep up with any early/CJ exhaust. A low riser port with equal work will approach 300 cfm and much better exhaust, and a real med riser will walk away from it with work on both sides.
- Craft Performance now has a CnC machining program for the heads that gets them about equal to an Edelbrock, not real expensive either if you are close by. May want to consider it if it's a performance build
- The chambers are slightly better than earlier styles, but you'd likely get more gain from good quench than you'd see from just chamber shape.
All that being said, I run a set on a 445 and will eventually be on a 462, because they do work if you spend some money on them in a vehicle where you need the exhaust port. In my case, a truck, in that case, you work the exhaust the best you can and then cam accordingly.
