I got a basic understanding that a tighter lsa and bigger .50 duration numbers effect idle. Say you have a voodoo 262 cam that is 262/268, 219/227, 530/542 lift and has a 110 lsa. Then you have a comp cam 275/283, 219/229, and 507/531 lift on a 110 also. They both have about the same .50 numbers and same lsa but different lifts and duration. How much does the advertised duration and lift effect idle if the .50 and lsa is the same? I'm just trying to get an idea on how rough the 262 will idle in my 408 bigblock since it has less duration. Thanks, Kevin

You can only tell if both cams are rated AND lashed the same if solid cams or rated the same at the same advertised duration check height if hy-cams!!

Oh, I do figure the 262 Voodoo should idle ALMOST like stock in a 408 BB motor... In other words, almost smooth, imho...

Usually cackle doesn't really start to get noticeable to up about 268/270 or so in the 350 and bigger motors, again, jmho...

I say this b/c "smoothness AND cackle" is in "the ear of the listener" sorta deal...

He, He!! Some guy's consider a Pro-Street cam streetable so go figure????

pdq67

I was kinda figuring that the 262 wouldn't idle like expected because the mild duration. Now I'm debating between the 268/276 voodoo cam with 227/233 .50 and 542/554 lift on a 110 or run Harolds old 276/286, 221/230, and 515/515 lift on a 112. I ran the 280/288 in it but because of oil problems I'm going through the whole motor and am dropping the gears from a 4:10 to 3.55 or 3:42 with a 4 speed. I might just run the 268 since I got the 4 speed and it would probly be more responsive then the 280/288 would be with less gear. I got a little bit of thinking to do. Kevin

Everyone,

The only comparison between the VooDoo 262 BBC cam and the Comp Cams 275/283 Daul Energy BBC cam is at .050. My cam measures 132/140 at .200", their's measures 123/136, quite a difference. I also have reason to believe their cam is SYMMETRICAL, while every one of mine are unsuymmetrical.
All of this will produce a difference in idle and vacuum, and in cylinder filling. The VooDoo will make a lot more power, period. I haven't dyno-tested the BBC VooDoos, but the bottom parts are identical to the SBCs, only with a little less lift and a more-rounded nose.
It will idle a little more aggressive than the 276/286, 221/230......

UDHarold

Harold I just wanted to make sure that the 262 would have a rough idle before I purchased it. I'm not a cam expert but it just had me a little concerned that it would idle a little smoother then I want because of the advertised duration, but as you pointed out theres alot more to how a cam idles then I thought. Thanks for giving your input and clearing up any second guesses I had. Kevin

It will idle a little more aggressive than the 276/286, 221/230......

UDHarold So the new VooDoo 268/286 will be a noticeably better performer in a 454 with about 9.0 to 1 compression. Right?

James,

The VooDoo 268 will definitely out-perform the old UD 276/286!

UDHarold

The VooDoo will make a lot more power, period. I haven't dyno-tested the BBC VooDoos, by Harold

I guess you're pretty sure that they will make more power :confused: I saw my first voodoo ad in CHP this month.

RapidRobert,

You're one up on me. I haven't seen any of the VooDoo ads yet, I'm not allowed input into the advertizing side.....
However, my belief on the power is really my belief in the Laws of Physics/ThermoDynamics, etc.
All my designs since 1977 (at Competition Cams!) are based on simple Physical Laws. If one cam opens the intake valve later than another, it will have less reversion. If it opens the intake valve FASTER at the same time, it will gain in high-lift area. Whenever you have a combination of less reversion and increased high-lift area, you get INCREASED cylinder filling, for higher cylinder pressures and more torque.
By also doing the same thing on exhaust, you get more work out of the cylinder, and more torque applied to the crank.
So by using unsymmetrical cams with good high-lift area, you get better cylinder filling, and better recovery of torque by the crank, ie---More BHP and Torque, EVERYWHERE!
It's worked for me for 28 years.......
The various improvements over the past 28 years have come through increased understanding of cam design technique and increased mathematical complexity. The basic theory is still the same.
The VooDoo line will make more power than the old UD hydraulics, even thought the old UD hydraulics still make excellent BHP. Heck, even my old 268 High Energy design is still a good worker!!!
I will soon have outside, independent, dyno tests on my new SUPER K series of roller cams, and I predict they will be greatly improved over the old 288/296R series, the most popular series I every designed.....

UDHarold

Harold just wondering how old are the old cams like the 280/288?

1982.......

UDHarold

Harold I started to take apart my 408 and it needs more work then I thought. Some idiot assembled the motor, all the bearings are scratched up and I found grass in the coolant passages. I shouldve went through it before I put it in but I thought it was ok because it was rebuilt and never ran. Anyways I pulled my original 396 out when I wiped the cam and it needs less work to get going. It would have a little over 10.1, would I still be alright if I used the 262 on a 110 lsa? Thanks again, Kevin

Harold I just wanted to make sure that the 262 would have a rough idle before I purchased it. Why is rough idle a good thing? Wouldn't you rather have an engine that makes the same power but generates more vaccum at idle and gets better MPG?

Personally, if the Voodoo 262 idles smoother than a competitors 275 cam but makes the same, or more power, I would think that would be a much better cam. :confused:

Well in my opinion when you drive a ss with a big block it should have somewhat of a rough idle. My favorite sound is a cam that lopes, its just preference. I wasnt interested in the comp just wondering how the 262 would idle to something I thought was similar but wasnt. I wouldnt buy a cam from anybody but Harold since he designs excellent cams and takes time out of his day to answer questions here.