[Cliff R]

"Apples to oranges comparison."

You are correct.......with all those aftermarket "high performance" parts the engine ahead of us should have made a BUTT LOAD more power, at least if you are buying into all the excellent advertising the companies making them tell us about them.....FWIW......

I'm not into "seat of the pants" feel or testing, and avoid parts that don't make the grade or have issues associated with them.

The XE cams are simply a direction I will not go with these engines. Right to start with they recommend too much spring pressure, which is hard on everything above the lobes. They also throw the valves around with a lot of authority. Fine for reducing overlap and getting better .050" numbers but with Pontiac heads and flat chamber floors and 30 degree valves/seats you are NOT taking advantage of the excellent low lift numbers.

Comp and other cam companies tell us that we will make "more power" with fast-ramp designs, better vacuum, improved throttle response, fuel economy, etc, etc. That sells parts but the reality of the situation is that shorter seat timing and greater .050", .200" and more lift is easily trumped by the valves being off seat longer. Folks are quick to look at .050" number but fail to realize that "time" in milliseconds adds up quickly to more opportunity to move air as the engine increases RPM's and the cycles are happening more times per second.

If you really want to make more power with shorter seat timing move to a roller profile instead. When you take the limitations of the lifter diameter OUT of the equation, what they tell you becomes possible.

I actually have a customer who used an XE cam in a 455 build and made excellent numbers. To get them he changed to 45 valves and seats, and HEAVY porting under the valves and short-turn in the heads. He installed ultra light parts above the lifters, including pushrods, rockers, and titanium valves/retainers.

The dyno results were actually quite impressive. Even so having to do all that with your basic "street" engine doesn't make it from a business standpoint and why jump thru all those hoops when you can make the same power with slower ramp cams, lighter springs, less expensive valves, retainers, etc.......