LSA Question

Newbomb Turk said
Do you ever consider RPM? Or intended usage? Because that is what makes the difference.

Let’s take the first one. RPM. You lose some power past peak with a tighter LSA. If you can drive and hit your shift points it’s not a big deal. But if you can’t hit your shift points, you may want a wider LSA to let the power past peak carry longer.

What about intended usage? Well, a powerglide car will not want a tighter LSA. Especially if first gear is in the 2.0 range (or whatever the OE first gear was because it’s a PG and I don’t really give a single **** about those) because how far the RPM drop is.

With the wider LSA you will hurt power below peak torque, and for all the street guys who think blazing the tires every time you touch the throttle is cool then you want to keep the LSA tighter.

Then there is tuning. I read all the crap on hear about tight LSA’s and drivability and it’s all nonsense IF you can tune. IMO, it’s way quicker and far more cost effective to do the tuning on a dyno, but you can do it in the car. It’s just 10 times harder and takes at least 10 times longer in the car.

So the short answer is it depends. For most guys just buy something on a 110 and go. There is a reason why Comp uses that as the de facto LSA for most of their street and street/strip grinds.

I also find it somewhat comical that so many guys claim they don’t care about power numbers yet every car forum everywhere has guys asking the same thing. It IS about making power, where you make power and HOW it makes power. If it wasn’t, we wouldn’t be talking about this right now.

You‘d be far better off spending the money for Billy Godbolds cam book. Read through it. Several times. As many times as you need to. I’ve already read through the book 3 times and have read parts of it probably a dozen times.

If you are into math, you can go to speedtalk.com and buy one of the few remaining copies of “The Horsepower Chain”. That’s an eye opener.

And don’t forget, you can’t change the LSA of a cam in isolation. The only way to change the LSA is to move the timing events to get what you want.

Billy Godbold's book Highperformance Camshafts and Valvetrains is a good book. I have read it once and as ou have stated you need to read it a few times.
For a person asking how cams can be advertised as both having strong torque, discussing IVC, IVO, EVO and EVC points will be probably past comprehendable until more of the basic knowledge is acquired. For this case, looking at David Vizard's Powertec 10 videos simplifies the procedure. There is one explains the 128 formula and another that explains what cam companies keep getting wrong.
The cam companies chose 110° LSA for shelf cams to account for the hot rod crowd that buys into the theory that if a bit of duration is good, a bit more will be better. Especially on the street a bit less duration and a tighter LSA will most likely give better performance. This limits the amount of overlap, for acceptable or good street running.