Re: Custom Cam
I wonder why some of your cams have so much duration?
The 422 cam is around 210 duration and .500 lift ---
Agreed. In my opinion, there is no need to 'cam' the engine for RPM like a N/A build. A conservative cam with adequate lift that maintains bottom-end torque and throttle response will run just as quick if not quicker than a 'big' cam. The turbocharger is where our power is, so if a strong, torquey street engine is the goal, we don't need to install big cams that reduce low-speed torque, manifold vacuum, throttle response, and fuel mileage.
For those reasons I had a stock GM roller core reground to my own specs since the regrinder shop is local. My cam has 206/206 @ 0.050", .488"/.488" with 1.6 roller rockers, ground on a 113* lobe seperation angle, 110* intake centerline (3* advance). I went with this profile for several reasons. I wanted stock or near-stock mannerisms, strong bottom-end torque, crisp throttle response and reasonable gas mileage. All of these things were achieved with this cam profile and I'm extremely pleased with it. I could have gone larger but I saw little value in a profile much bigger than around 206* @ 0.050". In fact if the stock cam wasn't so under-sized, I would have retained it, but it is simply too small in duration and lift, so without compromising street manners and the previously mentioned points a somewhat larger cam yields more power with little to no downsides.
I'm all about "instant-on" street power and torque whenever I can build and tune for it, so I tend to go more conservative in engine builds these days than in my ornery youth. Bear in mind this is all just my own preferences. YMMV :tup:
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