Does this prove David Vizard's 128 lsa formula ?

Bewy said
Ant,
Did you bother to watch the video of post #298???
You will learn a lot. I keep mentioning D. Vizard. He was contracted by Crane cams to do cam testing, which is where the 128 condensed rule originated from his cam program. At Crane, he tested over 19,000 cam combinations! When I meet somebody who has tested more, then I will take their advice.....In the meantime,..
Why would you bother ringing a cam company? If the phone jockey was any good, he would be building engines.....not looking at a computer screen.

Richard Holdener [ you tube ] has also tested a lot of cams. About a year ago [ maybe more ], he tested 3 cams that were identical except for LSA. It is on the net. They were tested in an LS engine with EFI. EFI, another wrinkle. The cam with the tightest LSA, which I think was 108, made more tq & hp.....than the other two. Seeing a picture here?
Below is one cam page out of DVs SBC book.
It is a bit hard to read, but the important points are this:
- looking at the bottom chart, because it has more categories, Street & Tow to Real Race
- engine size ranges from 302 to 434
- note that for ALL seven performance categories, the LSA stays the same for the engine capacity. 302 uses 110 LSA; 434 uses 104 LSA.
- what does change for each performance category....is the duration. Both adv duration & 050.
For Street & Tow: 258 adv & 206 @ 050. For real Race 304 adv/245 @ 050.

View attachment 1716258672

Those videos is what started this whole thread in the 1st place, all they show is tighter lsa generally makes more midrange torque (basically increases the tq per cid) but who is doubting that in the 1st place ?

None of them prove or even total disprove DV formula, but to me bring it into question that it provides the optimal lsa, it really only calculates lsa and no other cam spec, so it shouldn't be concidered a cam formula just an lsa formula, and it seem to pick a decent lsa, but not much evidence that if you go a few degrees wider or tighter than recommended that you'll lose 30-50 lbs-ft and not be picking cams like the 1% of builders and make 1.4 lbs-ft per cid like he implies.

If you want to use it to get a ballpark number, it seems fine, I'd would use it myself to at least know while choosing but I wouldn't necessarily limit my lsa choice to it's findings.

And I like his basic premise tighter lsa and less overall duration then people usually choose even there's really no evidence to say that's the best way.