I read Andy's article. It's a real eye opener.

But didn't you pick up a lot of hp in the other engine, going from 0.66 to 0.80? I thought that lift level put you over 800 hp and caused the block to crack.

It required a custom cam with awesome lobes to do it, but in this build, 0.75" lift level was chosen, resulting in 750 hp. Yeah, his ratio is 1.6 IIRC, but lift is worth noting.

http://www.hotrod.com/articles/how-to-get-755hp-from-your-wedge-mopar/

Wouldn't a NASCAR team cry foul and exit entirely if they were required to use 1.5 while competitors kept 2.0 ratios? If we tested a bunch of engines, wouldn't higher lift produce outstanding gains in many, if not most, configurations?

What are some things that can cause peak hp at 0.67" ? Just speculating:
Trick Heads claim to flow on par with ported E. Victor heads, but do they flow more like unported Eddy RPM heads? Were valve springs mislabeled or defective, resulting in float/instability that caps hp? Is duration curtailing effective CR? Is there something about the runners or cam that do not lack cfm on the bench, but do curtail velocity in practice? I don't know what happened in your test. You've given me something to think about.

In the meantime, imagine everyone demanding 1.7. Vendors get tired of broken part complaints and devise bulletproof systems. Everyone switches over. Armed with the knowledge that 0.67 is best, you request a lobe of just 0.39". Your 1.7 rockers get you to 0.67. Now you ask the cam grinder to drop the duration down. The rocker ratio adds a small margin of duration, but let's say overall it's a 15 degree drop in duration. Low rpm torque goes up. Driveability goes up. Valves close sooner so more CR is retained. People with dual plane intakes can ditch them in favor of single planes. Peak hp happens at a lower RPM, making dicey high RPM unnecessary. Low duration usually means less overlap, which means fewer hydrocarbons, if you're into that. And when it comes to forced induction, duration must be low.

But the article spells it out in black and white. I'll consider myself warned.


Thanks