Originally Posted by
wa04compg
Here is a quote from Overkill:
Just interested because I've personally installed dozens of cam setups, XP and custom with similar lifts, with LS6 springs and I love them. I dynoed 321 or 324 whp back in 03, was a NIC record at the time and stood for a couple years, was an XP cam with 1.75 modified rockers on the intake and LS6 springs. I also remember swapping to 130# springs and snapping those reuseable rocker arm bolts on two separate occasions, the setup was never reliable again until I redid everything, different heads and custom cam. I'm a big believer of sticking with LS6 springs, very reliable, inexpensive, never an issue making power. Last month I was contacted by someone with an Intense S2 L36 cam that we installed with LS6 springs and a stock timing chain setup, still running strong and that was done in summer 03 or 04, definitely a long time ago.
Having built or tuned lots of setups, I hope my opinion helps on this cam debate:
Intense S1X is a good off-boost cam, good crisp throttle response and it will also produce more midrange low boost torque. This is mainly due to the 111 intake centerline creating an early intake valve closing event, creating dynamic compression that will enhance power at low engine speed. In tradeoff, it won't make as much power at higher rpms, where a later intake closing allows more time for cylinder fill. It also has slower opening rates; in my notes of a Cam Motion printout I have 126/137 duration figures at .200" lobe lift, meaning although you see the .050" duration at 210/221 and good peak lift numbers, the cam lobe is pretty thin at mid lobe lift. Coincidentally, this cam is extremely similar to the CompCams catalogue cam.
Chris White XP camshaft will feel more dull in terms of throttle response and off-boost driving. Once into boost, it will have more midrange torque and top end horsepower, due to a later intake valve closing event, and a wider LSA and tighter .006" duration (seat-seat) creating less overlap. It's a simple tradeoff, can't have it both ways. The XP has faster opening and closing rates as seen with its 133/145 .200" duration figures, so the lobe is fatter at mid lobe lift by several degrees, and combined with the intake closing it makes for good cylinder fill.
ZZP NIC camshaft feels like an S1X in terms of crisp throttle response, but it lacks a little in midrange in-boost torque compared to the S1x and particularly the XP, due to the tight LSA and overlap it creates, which basically just wastes boost at lower engine speeds. Once at higher rpms, there's less opportunity for blow through to occur because of the speed of everything happening, so the duration helps cylinder fill and the NIC makes very good peak horsepower. You can run it ICed or non ICed, this whole "non-intercooled" scenario generated by its name is just for effect, the above results are the same, you need engine speed to overcome the overlap but once you get there it delivers very good power.
The S1x and XP camshafts both require milled retainers due to their peak lifts. The S1x is more valve spring friendly with its slower opening and closing rates but I personally ran an XP camshaft for 2 years on LS6 valve springs, and set at the time a non-intercooled horsepower record with the setup.
Double roller timing chains, I personally don't believe they help make the setup more durable. The Rollmaster chains in particular had a tendancy to stretch and I've seen some setups jump/chip a gear tooth because of chain stretch. I've heard of a Cloyes chain fitting but have no personal experience. I used to prefer the JP timing setups, before Rollmaster bought them out, because they had a stronger chain. I've seen some stock tensioners like the above picture after a year or two, and I've had others upgrade to double roller after a year or two and their tensioners looked fine. With a double roller, you also must must must machine the proper lip at the back of the crank gear, and ensure that the gears line up with a straight edge without the camshaft being pulled all the way forward. All this business with double front cover gaskets, machined pump covers etc, it's all an issue with the crank gear sitting too far forward from the block. This is why you will occasionally see the cam retaining plate crack and the cam gear kiss the front cover like I saw in my own GTP, the crank gear pulls the cam gear forward as the chain tries to align the gears.
I'll throw this out there, I developed my own custom camshaft for specific reasons and there's locals still running this setup after all these years. Overkill SBC2 camshaft, 3326/3307 HR116+2 grind number, its a 214/224 cam, 116LSA, 114ICL, .507/.507 lift @ 1.6 rocker ratio. It's essentially an XP duration and event timing that uses CompCams 4x4 lobes, same as the NIC cam. It creates XP like power but allows you to set up the valve train more simply. I liked to run LS6 valve springs but I did a few setups on L92/L76 valve springs which are very stock timing chain friendly, and yes a stock timing chain setup, regular LS1 retainers, no milled retainers or double rollers. My original 210/220 SBC beta tester (LS6 springs, stock TC) we did 301whp NIC on a TOG header, 3" exhaust, my ported Gen3, the old 4 bolt Northstar, intake and 3" pulley setup, and we ran out of injector at 5600rpm where power fell off, we would have hit 307-308whp at 6000rpm with larger injectors, 94 octane pump gas, no tricks, we had no problem making lots of power despite the "small cam". I don't carry camshafts for sale anymore but I've given the grind number of the cam, anyone can phone up Comp Cams, quote the grind number above and order it themselves, just credit it as an Overkill SBC camshaft is all I ask.
Bottom line is almost every camshaft on the market will give you noticeable and pleasant power gains. There is definitely a 10-20whp difference however between some cams, so you need to pay attention to what people are dynoing or running at the track and look for patterns if you want to maximize your investment. More aftermarket parts is not always the best power making or most reliable setup, you need to strike the right balance with the overall setup.