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Discussion Starter · #1 ·
I'm about to purchase a cam for my 400SB. What are the differences, advantages, idle quality, driveability, etc??? I hear a lot of good reviews about the 280H cam and I'm really leaning in to buying this. The 274H, I just happen to run accross and wasn't sure if it would be any different..if not better than the 280.

I like the idle, sound, and performance of the 280 and some people tell me it's actually small for a 400SB. To be honest, I'm a novice when it comes to camshafts and camshaft selections. So far I have been basing my decision on the 280 by what I've seen and heard from other people and their cars.

The tech at Comp Cams just told me that the 274 is just a streetable "milder" version of the 280. Not sure if that is true, but if that's the case, then the 280 will be my choice.

Please shed some light about these two cams, or if anyone has any experience with these...please feel free to tell me about it.

So-cal Jack
 

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The XE line is a more aggressive grind and will actually launch the tappet over the nose in a controlled valve float. That control off course is dependant upon how well you set up your valve train's geometry and the quality of the springs and the spring's installation on the head (shimmed for similar open pressure that live within the coil bind parameters).

I recommend the Magnum as a good grind for the street (I also like to look at the marine grinds with similar numbers because they are designed to live at WOT for hours to days at time without risking a failure).

I say all of this while I have an XE roller grind in my 406. I have been racing for decades, and I am familiar with the concept of preventive maintenance; that considers valve springs to be a consumable product. If you do not wish to follow my lead and trash valve springs and titanium retainers on a regular schedule then I would stick with the Magnum.


Big Dave
 

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Discussion Starter · #3 ·
Dave,

Thank you for your advice and experience. You have confirmed what many others have been telling me. I'll take the advice and run with it. I do think the Magnum is the way to go.

I just wonder how it will sound. :D

So-Cal Jack
 

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i have the comp cams 292 magnum in my car, and its a nasty little cam..sometimes i think its over kill..but when doing about 50 the car still pulls real hard..its real ratty sounding..no brakes though..lol
 

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i like the 280 cam myself. used it several years ago in a 355 and it performed excellent!!
 

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Does it have to be a Comp ??? The Lunati Voodoo series are pretty nice cams with agressive profiles like the Comp XE but a quieter lobe.

What is your compression ratio, what heads, gears, stall, etc? This all makes a difference when picking a cam.
 

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Discussion Starter · #11 ·
Thanks guys for all of your posts. I feel more confident now with my decision. It is hard to judge a cam on paper, and I know people out there are running the 280 in their 400 setups.

Doug and Chris....how much horsepower and torque did you increase with the 280 and what are the current specs now? (if you happened to dyno the car yet)

Thanks again for the advice and information.

So-cal Jack
 

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I never dyno'd the car but best time with a dead hook and 2.73's gave me a [email protected] now this was only using 1st and 2nd gears in a th350 auto,a torker intake,750DP Holley,and stock 400 heads home ported (1.94/1.6 valves). Once I put in the 3.73's and no changes it went [email protected] spinning running out of breath at about 5500 or so.

*Computer says 386hp at old combo
and with new heads claims 437hp

Rough Engine Horsepower Estimation Program

and another one... http://www.fastcoolcars.com/hp_calculator.htm

449 @ flywheel
359 @ wheels
 

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Discussion Starter · #13 ·
Doug, thank you for the info....again. :thumbsup:

I forgot to ask before.......how did you break in the 280H cam to make it last so long?

So-cal Jack
 

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Just as normal. Install and get timing as close as possible before starting, be sure to use lube that comes with cam, fire it up and regulate between 2000 and 2500 for 20-30 minutes or so, and then let it cool. Never let it idle during break-in, and be sure to use good oil (seems Rotella is the sh*t right now).

BTW, motor has been apart a few times over its life for a check-up (bearings) and new gaskets. Looked machine shop fresh,no sludge,cross hatch looked great,no ridge,and bearings were fine. Use a good oil and change frequently.
 

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Discussion Starter · #15 ·
Is it true that diesel engine oil is another motor oil to use during camshaft breakin, because of the additives that are not available in regular 10/30 or 10/40 oil? I was told it was ok to use for up to 3000 miles for the breakin only.

So-cal Jack
 

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Diesel rated oil (those that start with an API "C" letter instead of the "S" for spark) is the best quality motor oil you can buy for any motor. That is why it is more expensive for diesel grade mineral oil. If you feel bad having to buy seven or eight quarts for an oil change just think of the semi driver when he pulls into the service bay with a 42 quart oil system, and an air and oil filter that costs as much as a cheap computer.
 

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Shell Rotella is higher in zinc than any oil on the market right now, it's perfect for a flat tappet cam breakin, but 3000 miles,,,, NO WAY. Do your breakin, and change the oil and filter. Breakin by defination is two opposing components 'wearing' to common mating surface. You really don't want the debris circulating throught he bearings and everywhere. 5 qts of Rotella and a filter is going to cost $10 to $12,, CHEAP insurance IMO. It makes no sense to spend the bucks to build a performance motor, then not do everything possible to keep the oiling system clean and free of debris.


My SOP for any breakin is 20 minutes max and change the oil, Dyno room, first trip to the track, or 100 street miles,, and change the oil again. Then on to a regular maintenance schedule, with synthetic oil going in at the 3rd oil change.
 

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Rotella is just fine for any motor. I have used Moble1 in just about every thing I own and found that the only thing good about it is you don't have to change the oil as often.
 

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Discussion Starter · #20 ·
Thanks guys for the information. I have not too familiar with Rotella oil, but I'll keep my eye out for it the next time I'm a the store and maybe stock up on it.

So-Cal Jack
 
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