Your comments about a Magnum 280H Cam - Team Camaro Tech
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post #1 of 13 (permalink) Old Jan 3rd, 02, 07:58 AM Thread Starter
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I've about decided on the Comp Cams Magnum 280H...230/.230 and .480/.480 lift.

It's for a 69, M-20 4-speed, 3.73's.

406 sb, 5.7" rods, 195 AFR's, RPM Performer, Q-Jet, 9.5 cr, headers...will see an occasional 5500 arps.

1) How is the idle quality? (I'm guessing this cam would be smoother on a 406 than a 350). Would you say it's:

Smooth
Noticeable
Fair
Rough
Radical

2) How is the vacuum? I do have power brakes. Probably need 12# or more at idle.

Thanks in advance!

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post #2 of 13 (permalink) Old Jan 3rd, 02, 08:31 AM
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im running close to 14.5 vac and would say fair to rough idle on a 5.7, i love the 280H!

------------------
chris
1980 Z/28
350 .60 over stock bottom end world products torker2s 280H compcam edel.performer rpm,holly 750 dual feed.
2200 stall,- but still not done.
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post #3 of 13 (permalink) Old Jan 3rd, 02, 10:22 AM
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I use one in my 383,with rpm heads and intake ,3.42s and 700r4,It gos,idle is fair,vac.is ok.but border line.
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post #4 of 13 (permalink) Old Jan 3rd, 02, 01:42 PM
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I used two on two different 350's. Idle on both was noticable and vacuum was right in the 12" - 13" range. Just barely enough for power brakes.

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68 Camaro, 383 small block with TH350 trans. 11.98's at 111mph and never trailered.
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post #5 of 13 (permalink) Old Jan 3rd, 02, 03:08 PM
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I have a 280H in my 350 with 1.6 roller rockers. I think the sound is pronounced cause of the rockers but with the help of a vacuum gauge I got betwen 15 & 16 in/hg.

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post #6 of 13 (permalink) Old Jan 3rd, 02, 03:32 PM
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I have the same cam by Melling in my 406. It was very pronounced to me. Ran like a bat above 2500rpm!

My exhaust was 1.625" four tube hookers, a crossover, then two cheap 2.5" x 18" JCW turbo's under the front seats, then back to two 2.5" x 12" JCW turbo's at the resonator places and then 2.5" pipes out the back like stock just behind my rear tires.

Again, to me, it WAS NOISY!!

I think my main problem was that my 3.31's and 26.5" tires were too high for the cam to really work good as a daily driver around town. I prob. needed 3.73's with the taller tires!

It really pi--ed my wife off before I could build rpm idling around town to get it "off the cam" to keep it from bucking in second gear. pdq67
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post #7 of 13 (permalink) Old Jan 4th, 02, 12:03 AM
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<BLOCKQUOTE>quote:</font><HR>Originally posted by ORENCH:
I have a 280H in my 350 with 1.6 roller rockers. I think the sound is pronounced cause of the rockers but with the help of a vacuum gauge I got betwen 15 & 16 in/hg.

<HR></BLOCKQUOTE>

You say the 1.6 rockers make it sound more radical? How much bigger? I have a 383 being built that has a 292 magnum cam and 1.6 roller rockers. I wanted a big sound so I bought the 292,but then I found out that it acts smaller with more cubes so I got worried that it will tame it down. Should the 1.6 rockers save my rumble? Ive heard great things about the 280 magnum by the way and Ive heard it has a "crisp" rough idle in a 350 and has great throttle response for its size.
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post #8 of 13 (permalink) Old Jan 4th, 02, 01:49 AM
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I suppose that if the 1.6 rockers increase lift, then the pronounced sound is cause of that. A friend of mine has the same lift characteristics cam, (different brand) with original rockers in a 383 and it doesn't sound the same, more subtle. Anyway, you can hear mine at my sig.

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post #9 of 13 (permalink) Old Jan 4th, 02, 03:44 AM
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<BLOCKQUOTE>quote:</font><HR>Originally posted by nitrous383:
You say the 1.6 rockers make it sound more radical? How much bigger? I have a 383 being built that has a 292 magnum cam and 1.6 roller rockers. I wanted a big sound so I bought the 292,but then I found out that it acts smaller with more cubes so I got worried that it will tame it down. Should the 1.6 rockers save my rumble? Ive heard great things about the 280 magnum by the way and Ive heard it has a "crisp" rough idle in a 350 and has great throttle response for its size.<HR></BLOCKQUOTE>

1.6 ratio rockers do not significantly change duration - they only increase lift. there should be no noticable difference between the way a 1.5 and a 1.6 ratio rocker equipped engine idles - at all.

BTW the 292H will idle rough even in your 383.

------------------
68 Camaro, 383 small block with TH350 trans. 11.98's at 111mph and never trailered.
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post #10 of 13 (permalink) Old Jan 4th, 02, 09:51 AM
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I have the 280H with 1.6 rollers in my 350 - definite rough idle - not overly impressed at low end (probably my rear end ratio 3.08) but above 3500rpms it down out-n-out scares me.... wants to start running at this range - haven't found a top end (yet)

I have power disc brakes - haven't had a vacuum problem yet.... however, I have had to tweak the hell out of my Qjet (jets / rods / drill hole in throttle plates)

Love the sound....



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Steve
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post #11 of 13 (permalink) Old Jan 4th, 02, 10:14 AM
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Dobek, I recovered some low end torque after the 1/2" phenolic spacer instal. You may want to try it. Oh, it's true when you say drill hole in throttle plates, I solve it by opening the rears a little in my Holley 600 cfm.

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[This message has been edited by ORENCH (edited 01-04-2002).]
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post #12 of 13 (permalink) Old Jan 4th, 02, 04:54 PM
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<BLOCKQUOTE>quote:</font><HR>Originally posted by nitrous383:
You say the 1.6 rockers make it sound more radical? How much bigger? I have a 383 being built that has a 292 magnum cam and 1.6 roller rockers. I wanted a big sound so I bought the 292,but then I found out that it acts smaller with more cubes so I got worried that it will tame it down. Should the 1.6 rockers save my rumble? Ive heard great things about the 280 magnum by the way and Ive heard it has a "crisp" rough idle in a 350 and has great throttle response for its size.<HR></BLOCKQUOTE>

Man I found that my 292H wants to jump from the starting line. I have to keep two feet on the brake at a light. It will work best with a stall converter from 2,800-3,200 RPM that is what I am getting as well. The stock converter just doesn't give it the right manners. I think you will be quite satisfied. You will also have a lot of disatified mustangs in your town. I also have 1.6 rockers.


[This message has been edited by Deimos (edited 01-05-2002).]
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post #13 of 13 (permalink) Old Jan 4th, 02, 11:24 PM
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I have the Comp 280H and I love it!!! I think it is a great all around cam. It has rough idle, but that is what I love. I have 2 1/2 ex into flows that are dumped. It sounds so great.
Everyone always thinks I run a huge cam.

Michael
Old School for life

75 Camaro http://hometown.aol.com/fastchvy74/myhomepage/auto.html


[This message has been edited by Old School (edited 01-05-2002).]
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