Thread: Cam Choice help

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"62" 406 +.03
C8AE-J Heads
PI intake....matched ports
9.5-1 comp.
ss750an.....Quick Fuel carb._____was a Holley 750DP
Headers
T-10..........wish list is an early Wide Ratio Top Loader
3.50 rear 9"...........4.56 under the bench
3800 weight
Std. brakes and steering
Street, but not sissy street
Not a daily driver

Use to run the old C4AE-B Cam, pulled strong from 3k to 6.5k, this was with 12-1 comp.
Loved that cam, ran/sounded great, but keep hearing technology has come along way.
Thinking about Comp Cam 282S
OK, Pros, Cons, any input would be helpful
Thanks

282S is too much cam for 9.5:1 SCR, makes a weak-suck 7.898:1 DCR.

Use the 270S, makes 8.205:1 DCR.

33-244-4 - Magnum
Intake opens 6 degrees BTDC @0.050" tappet lift
Intake closes 38 degrees ABDC "
Exhaust opens 42 degrees BBDC "
Exhaust closes 2 degrees ATDC "
Intake centerline 106 degrees
Exhaust centerline 114 degrees
Lobe separation angle 110 degrees

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C4az 6250 d

So if I moved to say 10-1 SC where would that put me as far as DC? Sorry I’m completely lost with cams.
I’m looking at 9.5 SC to give me some ignition timing room using 93 octane, but the way this sounds I may have the room using this 282S at 10.1 SC. Not trying to tell you anything Tech just very confusing since Comp Cam sez 9.1+.

As far as the C4AZ –D cam that Jerry mentioned, I don’t know much about that or if it’s even still available

Thanks guys all help is greatly appreciated

Originally Posted by Ranch

So if I moved to say 10-1 SC where would that put me as far as DC?

That would put the DCR at 8.3:1, but the problem with that is that you're using iron heads. Word on the street caps iron heads at 9.5:1 and aluminum heads at 10.5:1 for use with widely available pump gas. Now, you may get away with it if you tightened up the squish/quench to 0.035" to 0.040" and/or maybe used water injection. Then again, you might be just fine with 10.0:1 and iron heads. It's just that I don't want to counsel you to do something that I myself wouldn't do.

Originally Posted by Ranch

Sorry I’m completely lost with cams.

Me too, I know just enough to be dangerous, so I tend to lean to the conservative side of the issue because I'm dealing with other folk's time and money and I want everything to turn out well for them, even if there is a little left on the table. I figure it's better to leave 10-15 hp on the table and shoot for the sweet spot in the middle than it is to create a motor that is on the edge with what I would consider too much cam for the application and have a soggy bottom end that would have to be crutched up with more converter and more gear. If you feel you need more power, change pistons and bolt a 3.98" arm into the block, then invest in some aluminum heads that will breathe far better than those iron relics you're using now. I don't intend for that to sound mean spirited either, I'm just being real with you.

Originally Posted by Ranch

I’m looking at 9.5 SC to give me some ignition timing room using 93 octane, but the way this sounds I may have the room using this 282S at 10.1 SC.

And I absolutely agree with that thinkin', but you'll have to watch closely for signs of detonation. Purchase a Longacre loupe and find a place (dragstrip being the best) where you can make a full-power pass, then go to neutral and chop the ignition. Coast to a stop and pull the plugs right there. Idling back to the pits will re-color the plugs and give you an erroneous reading. The first signs of detonation will be little black spots on the insulator that look like someone sprinkled pepper on them. That will be oil that is jetted out of the top piston ring lands from the sledgehammer blows of detonation. If allowed to continue with that tune, the next thing you will see is silver-colored specks on the insulators. That would be part of the pistons that melted from the excessive heat of detonation.
LONGACRE 50884 Spark Plug Viewer

Originally Posted by Ranch

Not trying to tell you anything Tech just very confusing since Comp Cam sez 9.1+.

I won't attempt to argue with CompCam techs, they know their products far better than I do, but I looked at similar specs from a couple of other grinders and they seem to favor 10.0:1 to 11.5:1 for cam timing in that 282S range. And another thing, as I've said on here and other forums many times before, I dislike the idea of yanking the valves off their seats with a numerically low Hydraulic Intensity in a street motor. The 282S cam has a HI of 46 and I would want another 10-15 degrees of difference between advertised and 0.050" for a street motor. If you are building a race motor, yeah, yank 'em open and slam 'em shut and get all the valve lift as quickly as you can and put up with noisy operation, but this application is a street motor, where longevity and quiet operation trumps horsepower in my opinion. Harvey Crane used to grind all his cams on a HI of 62 and Harvey knew one hell of a lot more than some of these yahoos grinding cams today in my opinion.

Originally Posted by Ranch

As far as the C4AZ –D cam that Jerry mentioned, I don’t know much about that or if it’s even still available

The C4AZ cam had 324 degrees duration and 112 degrees overlap and might want SCR on the order of 12.0:1 or better, so it may be a little too healthy for a street motor that has to operate on pump gas. Jerry has probably forgotten more than I ever knew, but that's just my opinion.

Originally Posted by Ranch

Thanks guys all help is greatly appreciated

You're welcome, keep those cards and letters comin' in.

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Tech----for the amount that I've forgotten--------leaves a very huge amount that you could know and probably do--whats SCR? is that super coupe reardrive? or single cam rotary? then maybe DCR is a dual cam rotary????

Have a good week end-wish I was in Pomona

Originally Posted by jerry clayton

Tech----for the amount that I've forgotten--------leaves a very huge amount that you could know and probably do--whats SCR? is that super coupe reardrive? or single cam rotary? then maybe DCR is a dual cam rotary???? Have a good week end-wish I was in Pomona

Static Compression Ratio and Dynamic Compression Ratio.
I don't go to the drag races anymore. After you have been on the inside of it, it's pretty hard to go and have to be on the outside of it. Might be like you having to stand outside a Boeing and look at it rather than climbing into the left seat and flying it.

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Yep--Now a days, I look up at those jeyts going over and the thought that pops up most often is that the sun will be in that guys eyes for the nex 4 hours ( or 6 ,7,8)

Drag racing------I still like to go and see and say high to all the guys---just sometimes I'll be in a pit area or trailer with the driver, crew guys or even owner and some young whipersnapper will try to run me out

Tech & Jerry Thanks for the help
That C4AZ-D looks close to the same numbers as the over the counter C4AE-B (324* dur.), Ford recommended for their Medium and High Riser. That’s the cam I took out of my engine when dropping CR from 12-1, that cam did love up to 6K+. The Comp cam 280s is pretty close to those numbers trying to compare old numbers with new @.05 isn’t easy. Now the C3AZ-AA (306* dur. cam that came in most 427s) looks kinda close to the 270s, I ran that Ford cam back in the early 70s. Those two are hanging off the ceiling now.
Was thinking about Ed heads but that might be in the future, they are about 5 or 6 CCs smaller than my C8AE-J’s so that would give me another .5 more compression. Besides my eye candy trips set up is matched to the iron heads.
Looks like I’ll be taking a second look at the 270s.

I was trying to post the numbers for those two cams maybe for your comparison, but the chart got all haywire on the copy/paste.

Thanks again

Tech & Jerry Thanks for the help
That C4AZ-D looks close to the same numbers as the over the counter C4AE-B (324* dur.), Ford recommended for their Medium and High Riser. That’s the cam I took out of my engine when dropping CR from 12-1, that cam did love up to 6K+. The Comp cam 280s is pretty close to those numbers trying to compare old numbers with new @.05 isn’t easy. Now the C3AZ-AA (306* dur. cam that came in most 427s) looks kinda close to the 270s, I ran that Ford cam back in the early 70s. Those two are hanging off the ceiling now.
Was thinking about Ed heads but that might be in the future, they are about 5 or 6 CCs smaller than my C8AE-J’s so that would give me another .5 more compression. Besides my eye candy trips set up is matched to the iron heads.
Looks like I’ll be taking a second look at the 270s.