The stock valves are fine.

But hey keep in mind that cams are not perfected for this vehicle... You'll need a major custom dyno tune if you install cams. There have been several stories of people losing power on the low end too. One guy got great gains though. Again, youll need a custom dyno tune done. Cams + install + custom tuning will add up very quickly...

If you're having the engine opened up like that then have as much work done at once that you can afford...

 

I have a Crower custom grind, but similar to the Stage 3 from Comp Cams.Here in Houston, Fast Lane has quite a bit of experience with cams on the S197 (mine was the first one they did). It took several dyno runs and tuning over a period of several months as they gained more knowledge in how to really make the cams work. Make sure you find a tuner that knows Mustangs. Normal tinkering with spark and fuel curves will get you decent gains, but to really make them work, they need to get into the code that controls the valve timing (remember we have variable valve timing) - this is where they'll earn their money. My car is going back this weekend to get some more tuning from what they've learned since my last visit 9 months ago. I'm hoping we can hit 350 rwhp, but it's been so hot and humid lately that may be out of the question.

One of the things you'll notice is that you may not see huge gains in peak torque, however the curve will be much flatter and the torque won't decay as much in the higher rpms like a stock engine, thus you shouldsee a very good gain in HP. I gained 36 hp after the cam swap, but I also already had LT's, and the CAI. I noticed it pulled much harder above 3500 rpm, and keeps on pulling hard all the way up to the shift point.

One other note: Nick at Fast Lane called to tell me that some of the cammed cars were experiencing broken valve stems(where it connects to the spring). If this happens, the valve falls into the engine and then things get expensive! Although with the new springs and cam I could go up to 7000 rpm, I don't so I'm not too worried about the valve issue. The guys experiencing the valve failures apparently dog the sh*t out of their cars. If you plan to go high in the RPM range, then consider a valve swap too - of course if you miss a shift on Nitrous, you may find yourself replacing more than just the valves.

 

IMO if you do cam s you might as well do head work while you are at it.

 

Don't bother with all that "mad tuner" custom work. Just buy a good set of heads like these with the option for valves, springs, retainers, Seals, Locks, & Locators, etc.....
I saw somewhere that some aftermarket heads were getting gains of 100whp with cams. Check out their flow charts too...
http://www.blowbyracing.com/bbr-3v-heads.html

 

+1 on the heads and cams at the same time. I am currently installing the ford racing heads with crower cams similar to comp stage 3. I already have all the parts, just waiting for it to cool off a bit and install them.