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Discussion Starter #1
LSA?

From what I've seen you nos guys really like alot of duration as well, true?

I found a cam w/1.6 .739 .693 274 282 112lsa.

This looks like a great cam for me to bracket race N/A but be able to spray it on those nites for heads-up or other special occasions.

I want to use this with my AFR 220s and a smaller motor, I'm thinking a 380" right now, 3.5 stroke, 4.165 bore.

Any thoughts?
 

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Discussion Starter #5
I don't have one as of yet, I was looking at the one, or one like it above.

R U asking about the installed degree? Like 106 or 105, is that what you mean?

It doesn't say, here is a link to the catalog page, its the 2nd one down in the Mech Roller Drag race section.

Maybe I'm missing something.

http://www.compcams.com/Technical/CurrentCatalog/HTML/128-169.asp
 

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Yes I was asking about the CL of the camshaft, 105 106, yeah them kind of numbers.
In your other sbc did you set the cam in by these numbers? 105 or 106
Just how did you set that engine up? Did you use the CL method when you degreed in the cam? that thing should have went better than that I would think, that thing was pretty numb, that engine should have broke that truck in half!! LOL just a figure of speech.You had problems in the CL area or you must have had some weak valve springs.

That page wouldn't load up all the way, I'll look in my book and get back to you on a grind number.
 

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That cam you have above part #12-817-9 or grind#307RXD-12 is not a very good choise, thats for a Comp Elim. car and my opinion it wouldn't work and it would be hard on parts, looks like alot of maintainence to me, you'd have to turn that thing inside out with the revs, you don't want that.

If it was me and I was going to bracket race and spray some you might want to go with a part #12-900-9 or grind #288AR-6 and thats my opinion with the heads you have right now I would think this would work good, and you still would be able to spray it some also.
The cam specs are
288 296 @ .050 252 258 630 630 LSA 106

or you can call tech @ Comp Cams and see what they would recommend 1-800-999-0853

Tom
 

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Discussion Starter #8
Thanx Tom.

We set the last cam in at 106. And the higher I shifted the quicker it went. My best passes were at 8k. Seems to be a 421 shouldn't need to go there, but......

The cam before, we set in at 102, and it ran a little slower, but the suspension wasn't as dialed in as now. It was w/1.6 .688 .668 264 268 106 LSA. Its in the 406 now and I lost about 2-3 mph, and about 3.5-4 tenths in the quarter, 60' was only 7-9 hundreths slower. Tighter converter.

I sprayed the first cam, last one mentioned above, with a 100 shot and picked up 2 tenths in the 1/8, 4 tenths in the 1/4, then hit it with 225 and only picked up 2 tenths more in the 1/8. I did pick up 6 mph in the 1/4 on the 100, I didn't run the 225 shot the full 1/4. I felt the narrow lsa was keeping me from seeing better gains on the spray. Yes...No?

Don't you feel that the short duration on your cam choice will make my heads even less effective? It seems I need to over come the lack of airflow I have by allowing the valve more time to fill the cylinder?

Thanx again for your time.
Doug
 

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Doug

I just felt you was over cammed and under flow on the heads,this cenero is like trying to put a marshmellow into a piggy bank, the heads are chocking the engine up, it may even be doing some reversion,

Thats why I chose the cam I did, could go maybe a little more on the duration,

how much does the S-10 weigh?
I'd try with maybe a little more duration, but thats about it

I have used such a cam like this in the past and had good results with it

Tom
 

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An other cam to consider with a little more duration would be part number 12-908-9
or grind # 300BR-6
specs, 300 308 @.050 264 270 630 630 LSA 106

just my .02

Tom
 

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Discussion Starter #11
O.K.,

So you're saying I may be causing a negative flow effect by (a) Leaving the valve open too long? (b) Opening the valve too far?

Hmmmm, see I thought I was trying to crutch the lower flow of the heads.

The truck is 3170 w/me. I race it in the same trim I drive it.

Tom, I have a brand new cam, it is a w.1.5 602 625 261 267 @ 050 108lsa. How does that sound? I could run or would run 1.6 rockers.
 

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Only thing doug, to run nitrous you want more duration on the exhaust to compensate for the smaller valve, it is best to stick with the 1.5's in my opinion. That cam may work for you, I'd try that cam and set it in straight up, meaning set it in @ 106 CL
Duration looks fine,that would work in that weight of vehicle, just my .02

Yes Doug, that chocking of the heads may be causing some reversion,IE making it lean and not running optum, thats what I'm saying, you can only get just so much into the engine as to what the heads will flow,leaving valves open so much like the other cam you had, it will have to turn over 8000 rpm just to start to make some power, I'd scrap that route! thats costly way to make HP, get your revs down to 4500 to 7500 rpms, just my opinion
Tom
 

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Discussion Starter #14
Tom, its funny, my heads after hand porting, are flowing almost identical #s as the cnc #s from AFR.

Well, I had sold the 18*s I had, but now the guy doesn't want them due to the cracks.

Looks like I'm going to have to bite the bullet, quit being lazy get that 3rd job and put the 421 together with the 18s.

Now, I know those heads flow!!! And I have really been wanting to run 9s on motor anyway, so I guess I'll sell the 220s and use that for headers,pistons etc....

Any thoughts on a cam choice there? I want to stay in the 12.5 to 13.5 comp range, so I can run the more economical 110 fuel, but would really like to get in the mid 9s if feasible. I'd still like to do the occasional spray too.

Again, I do appreciate your time.
 
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