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Old March 9th, 2012, 08:23 PM   #1
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Comp Cams magnum 280H

I'm getting ready to reassemble my engine,76,stock bottom end,fresh #8 heads,Magnum 280H Cam,stock intake,Hooker headers,2500 stall converter,turbo 350 trans.
Anyone running this cam?
Vacuum available for power accessories?
Thanks.
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Old March 9th, 2012, 08:33 PM   #2
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I run this cam on my 350 . vacuum is limited for me it is usually 2 pumps for the brakes and vac is gone. I dont mind it i am adding a vacum res. to help it out. The cam does not really wake up till about 2500 rpm . I all i run is water pump and alternator. It really likes to idle at 750-850 rpm .
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Old March 10th, 2012, 07:32 AM   #3
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you say stock bottom end so i'm assuming it has the low compression pistons as well? truth be told you'd be better off with the 260 with the lower compression. it'll run but you'll be giving up performance... i speak from firsthand experience, when i was in high school i built a 455 for my '76 442 which had origionally been a 350 car. long story short the old man wouldn't let me build it with the high compression pistons (an effort to detune for a dumbass high school kids own good)... it worked. years later i built a 455 (high comp) for a suburban swap and i used a comp 260 high energy cam and holy ****!! that thing had ***** from idle to redline!
the suburban was a '73 2wd 3/4 ton tank that originally had 4.10's in the rear, man that thing hauled ***! way more fun than my 442. i did regear it to a 3.42 which made the cruise rpms more acceptable. was a great tow rig...

if you are running a low compression shortblock don't run the 280, it will be sluggish.
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Old March 10th, 2012, 07:40 AM   #4
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i just reread your post and noticed the stock intake, even if the intake is an early non egr unit that cam would be a bad match. with a stock intake i don't think i'd go above a 260... something to bear in mind is that the 260 beats the factory cam in both the lift and duration dept, lift by about .050" or so and the duration by several degrees...
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Old March 10th, 2012, 08:22 AM   #5
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I live out in the country..all the roads are 55 mph.
I do not spend much time in the city,idling in traffic.
I'm looking for a cam with good punch at the 3000+ rpm cruise speed.
I'm not against upgrading the stock intake,but Don't feel they are much of an improvement.
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Old March 10th, 2012, 09:39 AM   #6
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Gonna hi-jack this for a question: How much vacuum do you think a 299/299, 242/242@.050 hydraulic roller would draw in a 496?
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Old March 10th, 2012, 11:07 AM   #7
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I raln the 260 from comp cams in my last set up. It was a 9 to 1 compression engine it went 13.71 . That engine is now in my dads 77 pontiac bonneville. For a car with 2.71 ish gears it moves.
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Old March 10th, 2012, 11:50 AM   #8
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sounds like your mind is made up but the 260 really is the better choice for your set up...

the 280 will work but i'd be willing to bet money that the 260 would outperform it in your set up!!
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Old March 10th, 2012, 12:32 PM   #9
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I just built a Pontiac 455 with the 268H..not road worthy yet...still have the clutch and brakes to finish...but the car idles smooth.
Can't even really tell the motor has a cam.
I understand the extra cubes makes a difference...just looking for that nice lopey idle.
If you guys suggest I go smaller,I will go smaller.
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Old March 10th, 2012, 12:51 PM   #10
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If you want a lopey cam i have one i can sell you. It's the lunati bracket mster cam same as edelbrock rpm. I would suggest the 260h
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Old March 10th, 2012, 01:01 PM   #11
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here is the 260h http://www.youtube.com/watch?v=M14Vy...ure=plpp_video


here is the 280h http://www.youtube.com/watch?v=zU3Zx...&lf=plpp_video
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Old March 10th, 2012, 01:35 PM   #12
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With your low compression engine would not run the 280h cam. I would something no biger than 212 @ .050.
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Old March 10th, 2012, 01:41 PM   #13
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nobody love the lope more than i do but i'd go 260 every time... i've even thought about mentioning the 268 as a compromise but my gut still says no...
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Old March 10th, 2012, 03:26 PM   #14
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I'm thinking of keeping the stock cam.
Not even worth the headaches.
Thanks guys.
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Old March 10th, 2012, 04:08 PM   #15
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i don't see much in the way of headaches... just buy a 260 and stick it in there and run it, you'll be pleasantly surprised. it may not be the answer you wanted but it is the right answer...
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Old March 10th, 2012, 04:15 PM   #16
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The 260 has plenty of grunt . It works with stock valve train and will run on 87. I was more than happy with it's preformance.
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Old March 10th, 2012, 04:50 PM   #17
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Quote:
Originally Posted by bigD View Post
you say stock bottom end so i'm assuming it has the low compression pistons as well? truth be told you'd be better off with the 260 with the lower compression. it'll run but you'll be giving up performance... i speak from firsthand experience, when i was in high school i built a 455 for my '76 442 which had origionally been a 350 car. long story short the old man wouldn't let me build it with the high compression pistons (an effort to detune for a dumbass high school kids own good)... it worked. years later i built a 455 (high comp) for a suburban swap and i used a comp 260 high energy cam and holy ****!! that thing had ***** from idle to redline!
the suburban was a '73 2wd 3/4 ton tank that originally had 4.10's in the rear, man that thing hauled ***! way more fun than my 442. i did regear it to a 3.42 which made the cruise rpms more acceptable. was a great tow rig...

if you are running a low compression shortblock don't run the 280, it will be sluggish.
Ok so I was given a 280h and lifters what combo on a 350 should I go with to make it work ? I've asked 4 engine shops in az an no one has an answer
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Old March 10th, 2012, 06:12 PM   #18
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9:1 or higher compression (9.5ish would be even better), an edelbrock performer rpm or a holley street dominator intake (if you can find a used one as they dont make the olds street dominator any more) headers and 2.5" dual exhaust...
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Old March 10th, 2012, 06:12 PM   #19
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You need minimum 9.5 to 1 compression I run 10 to 1 with flat tops , a good intake like the eddy rpm, headers, 2500 rpm stall plus, good gear in the rear I run 3.73 gears ,
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Old March 10th, 2012, 08:28 PM   #20
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Ok thank you now to find it all lol this is a big help I really appreciate ur time
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Old March 10th, 2012, 08:28 PM
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