[bullheimer]

it shows that the sbc 355 with good stock heads has about 15 more HP with a 108 degree lobe seperation than with a 110 degree seperation. the reason cam makers go wider is for idle-ablity. screw that! i went with a smaller cam for idle ability! everybody recommended the cam i got and it has 110 l.s. i wish now that i either would have gone with a much bigger cam at 110 or just got what i have now at 108. that's on my camaro. a compe xe 262. (@445 lift)

for my 326 pontiac i got a summit 2800 cam, which is pretty mild in a 389 but should work great in my 326. all except IT'S lobe seperation is 112 degrees!! now i havent seen any charts on l.s. for pontiacs but i am already wanting to send it back (still in box) and get something else. question is

why is everybody recommending these cams and/building them at 110 and wider, when they run better with less l.s.? dont they think we are smart enough to pick a small enough cam if we want driveabilty on the street?

 

[machine shop tom]

I personally think David Vizard is over-rated.

tom

 

[firechicken383]

First of all, dont ever believe anything you read in a magazine.:nono:

Ok so the cam with a 108 made 15 more horsepower, whoop-itty-doooo its not the end of the world.

What about the whole torque/horsepower curve? All im saying is that if you build for peak horsepower number only?

 

[bullheimer]

the whole curve followed closely but was above the whole way, the 110 cam

 

[engineczar]

It probably peaked higher but the average is probably the same or better with more seperation.

 

[machine shop tom]

I suppose now that we all have been "enlightened", we can expect the cam manufacturers (what do they know, anyway?) to $hitcan all of their offerings that have more than 108 lobe separation. After all, who needs blower cams, marine cams, turbo cams, torque cams, etc.? Thank you, your highness David Vizard!

tom

 

[Cstraub]

To many variables decide proper lobe sep and centerlines. A 5.7 rod 355 and 6" rod 355 with everything the same take different phasing.

Chris

 

[Ghetto Jet]

Bull, lift on the xe 262 is .462"/.469"

 

[killerformula]

yeah really, what's the point of the article anyway? Some cams do certain things better than others... that's why the make more than one kind!

K

 

[johnsongrass1]

Another one of those.

Seems like about every once and a while I hear something about some new innovative high tech wizardry that takes everything that humans know and throws it right out the window. Forcing humans to re-evaluate physics as we know it.

Fortunately, it only last's about a week.

 

[Cstraub]

Hell some people listen to their neighbors about a cam that ran 20 years ago and they put that in their engine to see if it works. . .wrong cam. . .hell it happens everyday. I wouldn't worry about it....


Chris

 

[4 Jaw Chuck]

I personally think David Vizard is over-rated.

tom

I second that emotion.

 

[bullheimer]

not the second, sugar coated post, huh 4j?:mwink:


so y'all think the 112 cam from summit is okay? they had a pile of 114 l.s. cams in their line up (Summit brand) as well. i dont know why. i wish i could link you to their site (PHR) but my 'puter won't let me right now. he dyno'd 4 cams in both a 355 and a 383 with all different l.s.' and same lift. what i get here is that dyno stats are like any other stats, they can be manipulated to prove anything you want.

 

[MI2600]

Bull,

Was this an article or in a book? I'd like to see it.

 

[4 Jaw Chuck]

not the second, sugar coated post, huh 4j?:mwink:


so y'all think the 112 cam from summit is okay? they had a pile of 114 l.s. cams in their line up (Summit brand) as well. i dont know why. i wish i could link you to their site (PHR) but my 'puter won't let me right now. he dyno'd 4 cams in both a 355 and a 383 with all different l.s.' and same lift. what i get here is that dyno stats are like any other stats, they can be manipulated to prove anything you want.

Guy writes a few books plagirizing every single engine builders techniques and people think he's a God.

Whoop de doo.

 

[[email protected]]

AMEN, 4-jaw. AMEN!

 

[Super Streeter]

And of course we all forget about cylinder head flow balance.If you have a poor exhaust port,you can throw about 10 degrees more duration on the exhaust lobe to help crutch it up,but to avoid adding too much overlap when you do this,you can do well to increase the lobe seperation.Of course this doens represent the ultimate in Natually asperated engine building design{since sch and engine should have a good I/E ratio anyway},but it is something that sometimes needs to be done.
Oh,and how about running a restrictive incuction system to meet class rule,or how about having to run an exhaust system to meet class rules,all of these things might effect how you space the lobes on your camshaft.

 

[machine shop tom]

BUT, BUT, BUT, it was in a magazine! And it was by David VIZARD! And he used a DYNO! How can it not be 100% TRUE?????




tom

 

[TurboS10]

I could care less about whether or not vizard is right. I do know that most of the engine builders and back yard hotrodders seem to lean toward the tighter lsa for NA race engines. They seem to be make the engine more peaky and have a more narrow torque curve, but they also seem to make more peak power. In a racing application, that is key. On the street it is not. In a street car you dont run a 5500 RPM convertor to match the peak power range of the engine. Instead you have to comprimise peak power to accomodate the car that the engine is going in. It is all about the combination. In a race car you can build for the peaky engine manors, but on the street it does not make sense.

Chris

 

[malc]

I have in my 355 (can I say that) a Crane cam with 104º
lobe separation, no idle problems, Desktop Dyno "says"
I have 330hp and 400 ftlbs @ 4500 rpm.
(when it´s not leaking coolant)