I ran a xe274 cam for a couple years no problems with it FWIW 12.70@108 and 20 mpg. I had some lifter noise but I think it may have been the cheap summit lifters I was running. Cam looked like new when it was removed for a custom ground Comp cam with a little more duration 236 vrs 230 intake @.050 and 244 vs 236 exh and a little more lift as well as a 112 lobe center. I also swaped to Summit boxed E-heads and single plane intake, bigger headers etc...
the car runs ok after fixing some fuel system problems that were probably holding the previous combo up too.
I guess its all clear as mud really. I wonder if the advantage of the hydraulic roller is not fully realized in our engines due to the poor head design ? I was thinking about this. the hyd roller once it starts to open the intake really yanks the valve open I wonder if the bowl volume and port shapes are able to feed this sudden draw as effectively as some other makes. Ive read some cam articals where they were very concerned about this yank effect on the port and the design of the lobe in relation to proper velocity. Its kinda over my head a bit maybe but maybe this is another variable to look at. I read something on a chevy thread about the under valve volume needing to be a certain volume to satisfy this intial draw on the port before flow through the entire port was established. Maybe pontiacs respond to a slower opening valve due to port shape better than a fast ramp or maybe its just the fast ramp does not show as much of an advantage on a pontiac. I'm just thinking out loud here.