M20: 264 Stock Cam vs. 274 Shrick Cam

[KCLARK]

Can anyone explain the sizing concept of how aftermarket cam or more specifically a re-grind helps produce more engine power than the stock cam by providing more lift/duration. My thinking was that all a cam did was move the powerband, but it appears that many who have cams also produce more hp on the dyno, how is that? The stock cam is 264 on the M20 engine, and I just had a custom milled Schrick blank made to 274 by RaceTep.
What im not understanding is why my 274 cam which is SUPPOSED to be more agressive than stock have smaller lobes than my stock camshaft?
Can someone with some experience explain this (see pic), thanks!!

[EtaSport]

Its not always about the lift of the cam. Its more about how long it keeps the valve open. Longer the valve stays open, the more air and fuel you can put in the cylinder meaning the more power you can make. It also depends on the engine and your intentions. I had a reground 274 in my car and replaced it with the stock i cam. I prefer the i cam for the driving I do, and felt no power loss going back to it, probably power gain. It is worth the money for a billet schrick because you get the lobe height above stock and the duration. Its also nice because you dont have to buy adjustment eccentrics.

[mspiegle]

If they regrind it, they can change the durations, but it'll reduce the lift because you had to grind metal off the lobes. This is where the oversize eccentrics come in.

[nando]

regrinds are a waste of time. if you don't want to spend money on a shrick I hear catcams are pretty good.

I also got a supposedly "new" cam from racetep.com that turned out to be a regrind, it was pretty obvious too, especially when I got my (real) shrick next to it. There's no way you can adjust the valves with the stock eccentrics, and they don't even tell you that it's a regrind or that you need the oversized ones when you order. sorry but you got ripped off! a real shrick (or non-regrind) will increase both lift and duration, it's just not possible with a regrind. :(

[KCLARK]

So are you saying racetep is BULLSHIT even tho I ordered a NEW cam? How can I find out or prove that I have a regrind and not an original made cam?

[nando]

well the aren't regrinding a used cam, they are using a "new" one, but it's effectively the same; you don't get the increased lift and you need the oversized eccentrics to adjust your valves (the stock ones will not even touch the valve stems). I never spoke to them about it, I just got the cam I should have ordered in the first place (Shrick 284/272) and traded away the racetep cam.