Thanks for all of the help. I really appreciate the time all of you took to write your response. I may not have clearly explained what I am after, so I'll try to be more explicit. I have a few more questions because as you can see, I am still a novice when it comes to proper engine building. My racing days are long since over and I am trying to put together a fun cruiser. Extracting every last hp out of the engine is NOT my primary concern. I want low speed drivability, high torque, dependability, and a slight sound. I will sacrifice sound for the right combination of parts though. My engine builder seems knowledgeable and we have done a lot on a budget. He builds a lot of circle track engines and has been able to obtain high quality / low budget used parts. The engine has full roller rockers which should ease the strain on the cam lobes a little bit. However, I am not interested in too big a cam anyway. He originally suggested a Crane WG1170, grind 962H with an advertised duration of 272 degrees intake and 288 degrees exhaust, 0.450" I, 0.460" E and a duration of 224/224 at 0.050". The LSA is 114 degrees. I wanted a smaller LSA, but similar lift & duration. The fast acting cam is a consideration, but that is why I have narrowed it to two of the smaller choices. The engine is fully balanced and the builder says that it will be good up to 7000+ rpm. None the less, I plan to shift between 5600-6000.
I have looked at extensive dyno tests by many magazines on similar set ups as mine. With the XE268 cam, most of them show max hp at 5600 rpm and with the XE262 max hp is at about 5200-5300. However, in every test, max hp within 5-8 hp remains 400-600 rpm after peak. I also noticed that heads with smaller combustion chambers and more valve shrouding such as the Vortec heads push the torque and hp curves up 200-400 rpm.

Again, my builder likes the XE268 with the 4-speed as does Comp Cams. As far as bleeding off cyl pressure with the bigger cam, there are only 3 degrees of separation between the two cams for intake valve closure. Both of these cams show tremendous bottom end with good high rpm performance. In fact on the dyno tests, the torque and hp output between the two cams (all other factors being equal) only varies from 1 to 6 ft-lbs and 1-4 hp between 2600 and 4200 rpm.

When you refer to tight squish, I assume you are talking about head gasket compression. The Speed Pro hypereutectic flat top pistons come up to about 0.015 below deck height. I thought that a thicker head gasket would reduce running compression and reduce the chance of detonation.

I have read so many books and articles in an attempt to educate myself and make intelligent choices, I am more confused than ever.

With all of this, I have several pointed questions:
1. Can you explain why a tight squish provides less of a tendency to detonate? Is it because a greater swirl is obtained?

2. Why would a small combustion chamber (Vortec) raise the hp and torque curves of the engine with all other factors equal?

3. I am looking to keep shift points between 5600-6000 rpm. I noticed that with the long horsepower range on the dyno charts, these cams pull hard 400-600 rpm past peak. That means that a cam that peaks at 5300 could be shifted at 5800 before power really drops off. Conversely, a cam that peaks at 57-5800 is still pulling hard at 62-6300. That is faster than I care to rev. I don't know how to judge these powerbands for my application. Any suggestions?

4. I have read countless dyno tests on both cams from testing conducted by magazines and Comp Cams Powerbands can vary significantly from one test to another. This seems to be dependant on head design. Any comments as to why powerbands can fluctuate so much?

5. My engine builder says he can lower the powerband about 200 rpm by advancing the cam 4 degrees. This will also advance the point at which the intake valve closes, thus raising cylinder pressure. Could advancing the cam lead to detonation? Any other comments on advancing a cam?