Whether you can run a vacuum boost depends on not just LSA. You need to look at the actual valve events and other things effect it too like how open the throttle blades are. Usually I just add in using a vacuum reserve tank or vacuum pump and be done with the issue.
Nothing wrong in anything you said, but some changes in LSA would make many of those much more universal than they are now and not requiring a band aid of vacuum pump or can, and that is looking at all the events, not just LSA. Nothing magic there in any of the specs, but my guess is their target market doesn't know or care, just wants 100 bucks cheaper.
I would have to guess my question never got to Nutter, though, may try again for fun. I find it pretty hard to believe that unless Summit isn't stocking cores with enough spread, that it wouldn't be just a programming change, but such is life. I spec all my custom cams through Comp and Bullet, figured I'd do a test on a TFS 505 if they could accommodate the change, but no loss here
I don't this those running summit are car guys, more likely money guys.
Btw what LSA were you looking for? Most of those cams are on a 111 and one is on a 111.5 Really looking at them some are not that bad as far as overlap is concerned. A lot of I/E split on some too. Be interesting to see how they actually run, but as I said I'm not that interested.
As for vacuum pump being a band aid look at many modern cars and they use one, usually run off the cam. This is because they don't make enough vacuum. Keep in mind most vacuum boosters are designed to have at least 18" of vacuum. Yes you can get by with less, but I've found cars with 12"-14" vacuum can result in variation of boost. At least is something I've observed, but of course I tend to be sensitive to these types of things. Now a days I won't even do a vacuum booster when I can grab an electric booster from a Tesla and mod it to fit. Add an electric assist steering column from a Kia soul and no more power steering pump, hoses, and hydraulics to deal with, but I'm getting off topic here.
I change LSA based on overlap after lobe choices and what I need for customer and engine intent, not quite that simple, but easiest way to quickly explain it. It can range from 108 to 115 on most builds. However, on this one I wanted to see Summit's big cam spread to 114 or 115. Can't really say "can you revise your entire cam for me" but I did expect maybe an option to spread centers on a special order.
As far as being money guys, some of the best parts are coming from this company, glad to see them make a little. Trick Flow heads are owned by Summit Racing and their quality is fantastic and availability is good, although I sure wish they'd come back with their single 4 intake. As I said, I suspect either my question didn't get to where it needed to be or it's a stocking core problem, as you spread centers, the company has to stock semi-finiahed cores to meet that need, so maybe they don't see a need for the flexibility.
I am not against a can or electric pump if a customer wants it, but also have many on the street that are on resto cars that do not want any modern externals, and we can easily make 550 HP at well under 6000 and give them good vacuum by controlling overlap. When you do that, it makes for a very happy street car, and if the head supports it, can make some big power.
