i know the eagle heads can have the short turn and throat opened up as large as you want if you are willing to change out seats. i have seen a set of eagle heads that someone installed new seats and a 2.19 intake valve. so i would assume the 6.1s would be the same. with the stock seat the size is limited to 2.10. a apache head is the size of a ported 6.1 head from the factory. just my opinion, but i would sell the 6.1s and buy some apaches. i think youll save a bunch of money in the long run when your talking about running a valve that size. [/quote]



Well, the one thing I have plenty of is time so I'll think it over. Given that I'll have to replace the seats in either head to accommodate titanium valves, that makes me less enthused to make the change and sell my heads because of the possible lost value selling in today's market. I'll keep my eye out, I maybe able to find a decent deal on some 6.4L heads such that I can make that upgrade.