Originally Posted by RDY4WAR
The old V8 OHV engines have higher open spring pressure than a OHC engine since the springs have to control the weight of the rockers, pushrods, lifters, and any intertia and jerk in the system. That higher spring pressure gets multiplied across the rocker ratio as well like a torque arm. A spring that's 250 lbs force at .500" lift is 375 lbs at the lifter with a 1.5 rocker ratio, 400 lbs with a 1.6 ratio, plus the weight and inertia of the valvetrain.
This depends entirely on the operating RPM range of the engine and camshaft profile. Most non-HiPo FT cams were extremely mild and the stock springs quite weak. A 7K RPM Euro COB setup is going to be a more demanding environment than a 4.5K RPM 305 in a 1500 Silverado. Also, COB setups don't have the advantage of a rocker ratio to increase valve lift, ergo, the lobe profile is going to be significantly more aggressive, somewhat negating the geometry argument.
As an example, the cam-over-bucket BMW S54 has 0.457 lobe lift with 288/280 duration. That bucket and its lubrication is subsequently having to handle that extremely aggressive ramp and the spring be sufficient for an RPM ceiling approaching 8,000RPM. The venerable "30-30" cam from the HiPo Chevy 302 had 0.305 lobe lift (0.485 at the valve with a 1.5 ratio rocker) and 258/258 duration, so less aggressive ramps, but of course has to contend with the valvetrain mass issue and amplified spring pressure.
In contrast, your typical warmed-over 305/350 with a stock-ish cam like the Comp 240H is looking at 0.260 lobe lift and 240/248 duration, not a demanding application.
A buddy of mine and myself put together a couple of 355's "back in the day", one of which we fitted with a Lunatti Voodoo series camshaft, which had some pretty wild ramps. Broke it in on Kendall 15w-40 and that's what was run in it until the motor was pulled a few years later and we did a roller build. Cam was still immaculate, as were the lifters, which surprised us.