Got a cam recommendation, don't know what to think of it.

303Radar

303Radar

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My engine builder gave me the following cam recommendation:
CHW 283/288-HR112
intake lobe = HR283/335
exhaust lobe = HR288/335
duration @ .050 = 228/234
lift = .586/.586
lobe separation = 112
Recommend 4/7 swap firing order for supercharged engine.

However, I don't know how to read or translate this into anything which makes sense to me.
How should this idle and what kind of power (w/o the supercharger) should I be looking at?
This will be in my 348 punched out to a 431 with a compression ratio just shy of 10:1.
Thanks!
 
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Don Jacks

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Well in a heavy car like your El Camino,I think it'll do quite well.In a 431,it'll have a very noticeable lope at idle,but still pull nicely fom about 2500-6000 rpm.Your top end hp will depend on the top end componants on your engine[heads,intake,carbration,and exhaust].I see no problem with 1 hp per cu.in. with the right parts up top.The 4-7 swap wont do anything to help,or hurt power,I think it's more that thats just the way all the newer cam blanks are ground.You cant get one ground from Comp anymore that isnt ground that way anymore,and they probally grind more cams than anybody else.If you want a bit more low end,at the expence of a little top end power that you'll likely never use,advance the cam 4 degrees,if it isnt already ground that way.
 
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Don Jacks

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One other thing ,make certian that your hyd roller tappets are NOT the ones that are .300 in.taller than stock.Those dont work well in a W engine.
 
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poison ivy

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get a recommendation from your cam supplier,tell them, weight of car, other mods,trans,rear gear to run, and some specifics of your use of car.... then compare that to others, good info at the start is very important..don't over or under cam...
 
63 dream'n

63 dream'n

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[quoI e="Fathead Racing, post: 231884, member: 61"]I agree with Don (what else is new) the 112 lobe separation will give you good vacuum. That cam for those cubes is Fairly mild. Good cruising cam. Don't use Tri Y headers with that cam.[/quote]
May I ask why not the tri Y header design ?,don't they promote torque in your low to mid range?
 
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Don Jacks

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As Jeron Jardine pointed out,the tri-y is based on the firing order pulses.With the firing order changed with the 4-7 cylinder swap,the tubes would also have to be changed inorder for the header to properly work as intended.Makes sense to me.
 
303Radar

303Radar

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Supporting Member 2
poison ivy said:
get a recommendation from your cam supplier,tell them, weight of car, other mods,trans,rear gear to run, and some specifics of your use of car.... then compare that to others, good info at the start is very important..don't over or under cam...
Click to expand...
That is how the recommendation was made, I filled out an online form and the above was the cam builder's recommendation.
 
303Radar

303Radar

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Don Jacks said:
As Jeron Jardine pointed out,the tri-y is based on the firing order pulses.With the firing order changed with the 4-7 cylinder swap,the tubes would also have to be changed inorder for the header to properly work as intended.Makes sense to me.
Click to expand...
When I get closer to the exhaust system, I'll have to ask Jardine if they can accommodate the swap if I go that route. Particularly with a supercharged engine. After all, it doesn't matter what kind of air flow you can get in, if you can't get it out!
 
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Don Jacks

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I think it's a nice,conservative choice.If you do go with a blower,then the normal recommendation is to run the cam "straight up".[Do not advance it.] Jerod did say that he can build a header to compliment the 4-7 swap.
 
jim_ss409

jim_ss409

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It sounds like a good cam to me. :scratch
I think it should work pretty well both naturally aspirated and supercharged.
I might have guessed they'd have recommended just a little more exhaust duration, just because it might get a supercharger later, but I'm sure it'll be just fine.
I think it should give you a fairly good idle,,, just a bit of lope.
 
62impala409

62impala409

 
Supporting Member 1
Or you can spec out a regular firing order cam. My previous Comp roller cam had the 4/7 lobe swap. When I recently replaced that cam for one with a little less DRAMA, I went to Lunati Cams because they still offer a regular firing order roller cam just in case I decide to go with Tri Y headers down the road. I don't think anyone has any demonstrated any appreciable horsepower increases in a W motor with the lobe swap cam. Leo
 
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Don Jacks

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I think that the consideration is for more balanced harmonics with the 4-7 swap due to the increased cylinder pressure brought on by the supercharger.It ,to me, would be more of a durability thing than a power thing.
 
62impala409

62impala409

 
Supporting Member 1
Don, you are correct on the harmonics. When some cam grinders went to the lobe swap blanks a few years ago, there were some builders touting the power gains available. I don't believe those claims were sustained. Anyway, for my subdued driving to the drug store, harmonics are not a big concern.:laughLeo
 
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Don Jacks

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I'm totally with you there Leo.My little Comp roller is the standard firing order,and I like it that way!:laugh
 
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Don Jacks

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Brian,I think that I read that he's gong with Edelbrock heads.If so the added heat dispersion factor will be eqilivent to 1/2-1 point drop in compression ratio,plus the fact that he lives in a high altitude area[Colorado].It's close,but with the aforementioned atributes,and the detonation resistant nature of a w engine,and electronic fuel injection and timing ,he's likely ok there.
 
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