Solid Roller camshaft selection those of you running a 408 race application - lobe seperation

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9secRR said:
16.4 compression, 6400 stall, 7800 shift rpm.
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Love it! I’ll be just under 14:1, was planning for same shift rpm, and 6200 stall…will have to see I guess. Thank you sir!

Edit: found my cam card (just for the sake of parody within this discussion). Again, waiting to have the car back to get the engine together and on the dyno…guessing that’s a year+ out with the way I see things going.
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the more i think about it, the engine is not happy. with 12.5:1 compression, 660 lift roller, 4'' stroke, 320 CFM heads.... this car should be running 9.90's.

wondering if the cam was degreed? what's the timing at?

i still think it needs a different converter to wake the engine up, it's not performing the way it should.

if you have a 727, switch to a 904 as most people say 2-3 tenths faster with a 904. i've never compared the 2 back to back but that's what i have heard.
 
9secRR said:
the more i think about it, the engine is not happy. with 12.5:1 compression, 660 lift roller, 4'' stroke, 320 CFM heads.... this car should be running 9.90's.

wondering if the cam was degreed? what's the timing at?

i still think it needs a different converter to wake the engine up, it's not performing the way it should.

if you have a 727, switch to a 904 as most people say 2-3 tenths faster with a 904. i've never compared the 2 back to back but that's what i have heard.
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I switched from a 727 to a 904 back when I had a stock stroke 360 in the car and didn’t see a thing, was hoping to but didn’t.
I don’t know about 2 or 3 tenths.
I have heard a tenth or 1.5 tenths is common.
Regards the OP’s car, the other thing is, are the heads really as good as people think they are. That would be the thing to me.
I think when the other guy had it, weighed a little over 3200, and it went around 130 mph, or close to it, if memory serves. So I wouldn’t guess anything is off that much. To me, it would be more how good the heads really are as my first place to look. They have been redone, but I have yet to see those heads put up what I would call impressive track numbers they way they come.
 
9secRR said:
the more i think about it, the engine is not happy. with 12.5:1 compression, 660 lift roller, 4'' stroke, 320 CFM heads.... this car should be running 9.90's.

wondering if the cam was degreed? what's the timing at?

i still think it needs a different converter to wake the engine up, it's not performing the way it should.

if you have a 727, switch to a 904 as most people say 2-3 tenths faster with a 904. i've never compared the 2 back to back but that's what i have heard.
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Previous owner says cam was installed 4 degrees advanced, so I'd assume it was. Timing was at 34 degrees. I will degree the new cam in and new converter will be coming as well. I don't think the engine was happy either. This is why I did a leak down test on the cylinders and found 4 exhaust valves leaking to where I could hear it and feel it. Piston rings are find. Heads are getting redone, I'll install/degree in a new cam, new converter, and probably do something different with the exhaust, since it had full exhaust with tailpipes. My ultimate goal is to get in the 9.90's, but if it goes 10.20's id be happy.
 
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Since you’ve found weak cylinder pressure on half your engine, I myself would try the old cam out straight up without any advance and see how it behaves to establish a new baseline. The only way I can see a cam needing to be advanced in a four inch stroke LA is if it’s too large (I’m pretty certain that’s not the case!) and the car is under geared with too tight of a converter.
 
Garrett Ellison said:
Since you’ve found weak cylinder pressure on half your engine, I myself would try the old cam out straight up without any advance and see how it behaves to establish a new baseline. The only way I can see a cam needing to be advanced in a four inch stroke LA is if it’s too large (I’m pretty certain that’s not the case!) and the car is under geared with too tight of a converter.
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I mostly agree with this. I've stated in the past that this car with 29" tires needs either 4.56 or 4.88. The converter is definitely an issue as the car went faster with my spare converter in it. I do think the can needs changed as I believe Bill ran it before having the heads done and wasn't happy with the results. However, it was with a underwhelming converter.
 
rslscobra said:
12.25 to 1. Current cam 287/301 660/660 lift with a 108 lobe seperation at .050 254/268 and .440/.440
3350lbs Duster with 430gear and 29” tall tire.
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That should put you very close to your goals in a healthy engine installed on a 106 to 108 (maybe even a 110) with your present combination and converter.
 
73smallblock said:
I mostly agree with this. I've stated in the past that this car with 29" tires needs either 4.56 or 4.88. The converter is definitely an issue as the car went faster with my spare converter in it. I do think the can needs changed as I believe Bill ran it before having the heads done and wasn't happy with the results. However, it was with a underwhelming converter.
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Okay, thank you for clarifying! Yes, it could definitely absorb some more duration, and I was referencing the previously mentioned 4800 stall. Definitely better to go ahead and step it up now with a proper converter than to have to swap cams later…
 
Garrett Ellison said:
Okay, thank you for clarifying! Yes, it could definitely absorb some more duration, and I was referencing the previously mentioned 4800 stall. Definitely better to go ahead and step it up now with a proper converter than to have to swap cams later…
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I will be installing a new converter as the one 73smallblock had based on the results.
 
Garrett Ellison said:
Since you’ve found weak cylinder pressure on half your engine, I myself would try the old cam out straight up without any advance and see how it behaves to establish a new baseline. The only way I can see a cam needing to be advanced in a four inch stroke LA is if it’s too large (I’m pretty certain that’s not the case!) and the car is under geared with too tight of a converter.
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I have never run any cam that called for being installed 4 degrees advanced per the cam card, straight up.
 
rslscobra said:
Recommendations:

Racer Brown - 270/693 274/683 108 LSA 4000-7500
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If you're having a new converter built for your new cam, I like this one or the Bullet the best.
rslscobra said:
Bullet - 271/680 276/670 108 LSA 4000-7500
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A lot of users swear by their recommendations, I don't think you'll be disappointed. Notice how close they appear to one another and how they're right in the middle of the numbers of the recommended cams?
 
Newbomb Turk said:
I have. Most of them. If it’s 4 degrees advanced and the overlap triangle is shifted ahead then it gets retarded until the overlap triangle is centered.
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I have bought several cams from Dwayne for 4 inch motors. Always installed per the way they were designed.
Most anything designed to run 4 advanced( 108 at 104, 106 at 102, 112 at 108, etc) will be a dog out of the gate stood straight up.
I am talking something that’s ran at the track.
 
B3422w5 said:
I have bought several cams from Dwayne for 4 inch motors. Always installed per the way they were designed.
Most anything designed to run 4 advanced( 108 at 104, 106 at 102, 112 at 108, etc) will be a dog out of the gate stood straight up.
I am talking something that’s ran at the tra
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Post up your examples and I’ll look at them graphically.

You might be talking out of your hat, as that 4 degrees of advance may center the overlap triangle.

If you haven’t roll the cam ahead to make the car leave you have other issues.
 
Newbomb Turk said:
Post up your examples and I’ll look at them graphically.

You might be talking out of your hat, as that 4 degrees of advance may center the overlap triangle.

If you haven’t roll the cam ahead to make the car leave you have other issues.
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I am not a cam expert. Just installed them the way somebody who is, said to.
From what i understand, retarding the cam tends to perhaps help on the big end, but negatively affects the starting line.
I do know going to a wider LSA had a similar effect( killed bottom, was supposed to help the top) that I actually tried real world. Et slips hated the wider lsa( a lot)
Is that not true ?
Frankly, I have never heard of anybody I know who races not advancing a cam to where the manufactures suggests it to be
In other words, I have never heard of anybody with a 108 cam installing it at 108.
 
B3422w5 said:
I am not a cam expert. Just installed them the way somebody who is said to.
From what i understand, retarding the cam tends to perhaps help on the big end, but negatively affects the starting line.
Is that not true ?
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Not true. How many rpm does a 4 degree advance move down? 400??
500?

Even at 500 rpm you are so far below converter stall speed it shouldn’t matter.

I’ll say this and I know some will get all wadded up over it but this is what I believe. And that’s that moving the cam ahead to get more “low end” has far less to do with IVC and far more to do with EVO.

That’s why I’ve never understood the de facto 4 degree split. On virtually everything. Does everything need a 4 degree split?

Highly unlikely but Comp was setting the “standard” and that’s what they did. Just like the 110 LSA for so many cams. They did that because the 110 LSA fits far more cores.

That’s why I asked for your numbers. Let’s say you have a 108 LSA and a 104 ICL. If it’s not an off the shelf cam chances are the overlap triangle will be centered, or that’s the same as saying it’s in straight up.

I was running some numbers for my W2 engine. It called for a 111 LSA and a 105 ICL. When I put the numbers into the program I use to see it graphically the cam was straight up even with all that advance.

And it called for a 16 degree exhaust split.
 
I’m glad to see there are still several of you arguing, errr………. “debating” about the OP’s cam selection process/requirements.
 
I now view internet cam recommendation threads in the way I look at “what oil should I run” and “what are the best spark plugs” threads.
There are almost as many different responses as posts.

Everyone is sure their answer is correct…….. and no one’s mind is getting changed(mine included).
So I rarely make specific recommendations, cuz it’ll just add to the noise and create an opportunity for more arguing.

As I said in an earlier post, if you feel like you need assistance in selecting a cam, find someplace/someone you feel confident dealing with, and go with their recommendation.
And understand that whoever that is, and whatever they recommend…….. there will be plenty of people to tell you how wrong that selection is.
 
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Guys I am now working with Racer Brown for the recommendation. He went as far as saying he would grind two lobes on a scrap cam and send it to me to check clearance prior to grinding my cam. I’ll let everyone know the specs once I run the car. He has years of dealing with mopar combinations and dyno results. Will it be the best cam? Not sure, but will probably be one of the better educated guesses. Ty all tho I like reading all the feedback and opinions.
 
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rslscobra said:
Guys I am now working with Racer Brown for the recommendation. He went as far as saying he would grind two lobes on a scrap cam and send it to me to check clearance prior to grinding my cam. I’ll let everyone know the specs once I run the car. He has years of dealing with mopar combinations and dyno results. Will it be the best cam? Not sure, but will probably be one of the better educated guesses. Ty all tho I like reading all the feedback and opinions.
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Looking forward to hearing how it goes!!!
 
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