[Stan Weiss]

Originally Posted by Cliff R

I've witnessed a few dyno runs with Pontiac engines using iron heads and Comp XE cams. I've also had a good many customers (thousands actually) that used XE cams in their engine builds and many had dyno'd them. This would include a of other brands, Chevy, Olds, Buick, etc. They suck horribly in a Buick build but not sure why? I had discussions with Jim Weise years ago when he tried them in Buick builds and had to go back to the T/A cams he'd been using. Although they superficially showed some promise coming up thru the RPM range the Buick valve train didn't like them much and the engines went "dead" past 5000rpms and he even experienced rocker arm breakage. Power not only came right back no more parts breakage when he went back to T/A or factory cams in his engine builds.

Ya before you remind me I know that's not related to Pontiac stuff so I'll add this tid-bit about XE cams. I'm NOT fond of them and that's common knowledge on here. I can make a LOT more power with a similar size Crower cam in the same application without having to run a LOT of spring pressure or experiencing "lifter crash" at high RPM's. I'm never seeing as much power from Comp cams with iron heads, at least those with 30 degree intake seats. That shouldn't be surprising as the flat chamber floors and 30 degree seats thrive on low lift flow.

With all the bad rap I've given those cams over the years I have observed one success with them in a Pontiac engine and a few success stories here, so I'll add to them. It was a 455 set up for "stock appearing" drag racing. They "worked" the factory heads pretty hard (not even sure they were legal) and they used 45 degree intake seats. They also used super light valve train parts, titanium retainers, stamped steel rockers, etc. That engine cranked out pretty hefty power numbers and made nearly 90 MORE HP than a 455 another customer built using the same heads and XE cam a few years earlier.

I don't remember all the numbers or specific details from each engine other than they were both 455's, both used iron heads, about the same compression, same cam, factory intake, Q-jet and factory distributor. As good as the XE cam did in that one build I would still never use one. I do NOT like having to use a butt-load of spring pressure on a flat cam to keep things happy. It's just a personal thing, and why would I when I can make PLENTY of power with closer to stock spring loads and cams with a LOT less aggressive ramp profiles........FWIW.......

Cliff,
You answered your own question. Drag racing. Find someone running a "stock" Pontiac in NHRA and see what spring pressures they are running, along with tool steel lifters.

Stan