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509 cam swap in a 451

Garys1969RR

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I have a 451 with 13 to 1 C/R, 915 heads with larger 2.14/1.81 valves. It currently has a 509 cam which has 292 duration, 242 @ .050". And .509 lift. I am thinking about going to a Comp Cams mechanical cam. The 23-232-4. It has 282/290 int/ex duration, and .520/.540 lift. And 244/252 duration @ .050". My question is: will this cam offer much more in power output than the 509? It isn't much more in lift and a little shorter in total duration. Although ex duration at .050 is 10 degrees more. Anyone have any experience with these 2 cams? Thanks.

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I have heard that a mechanical cam will out perform a hyd cam with the same specs. I suppose thats due to a more stable valve train. Could I get good results by simply just using solid lifters on the 509 cam and setting valve lash at .005" or .006"?
 
13:1 CR is pretty high. What are the chances the piston dome is seriously affecting flame travel thus contributing to your problems?
 
I have a 451 with 13 to 1 C/R, 915 heads with larger 2.14/1.81 valves. It currently has a 509 cam which has 292 duration, 242 @ .050". And .509 lift. I am thinking about going to a Comp Cams mechanical cam. The 23-232-4. It has 282/290 int/ex duration, and .520/.540 lift. And 244/252 duration @ .050". My question is: will this cam offer much more in power output than the 509? It isn't much more in lift and a little shorter in total duration. Although ex duration at .050 is 10 degrees more. Anyone have any experience with these 2 cams? Thanks.

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I have heard that a mechanical cam will out perform a hyd cam with the same specs. I suppose thats due to a more stable valve train. Could I get good results by simply just using solid lifters on the 509 cam and setting valve lash at .005" or .006"?

A swap to a solid presumes you're having high rpm issues in the first place. How do you know this is a problem?

Is this just a general question or do you have a specific problem you're concerned about w/ the 509?

W/ 13:1 and a 451, I'd not be looking at OTS grinds.
 
I wouldn't choose to run a single pattern camshaft with 915 heads if I had other options.

I haven't mapped the lobes on the 509 and the XS282S, but once you consider the valve lash on the solid cam, the intake duration and lift is gonna be a wash. However, the 915 could use some help in the exhaust area and I think the XS282S with the increased duration would be of some benefit.

We did some tests and installed just a bigger exhaust valve (1.74 to 1.81, with some proper bowl blending) in a 906 and picked up 12 HP. HP increases were seen from the bottom of the rpm range to the top.
 
The torque curve on this motor seems to flatten out after about 5000 RPM. It pulls hard from 2200 RPM to 5000, then I have to shift, as power/torque is diminishing quickly. After shifting, it pulls hard again thru 2nd gear up to 4800 or 5000 RPM. I suspect the Holley Street Dominator intake is running out of ability to flow enough air at higher RPMs to keep up with the needs of the engine. It has fairly small intake runners, and was designed for a 383/400 engine. So I plan to install a Performer RPM intake at the same time I change the cam. The better flowing Perf RPM and the solid lifter cam should both help the higher RPM range.

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I wouldn't choose to run a single pattern camshaft with 915 heads if I had other options.

I haven't mapped the lobes on the 509 and the XS282S, but once you consider the valve lash on the solid cam, the intake duration and lift is gonna be a wash. However, the 915 could use some help in the exhaust area and I think the XS282S with the increased duration would be of some benefit.

We did some tests and installed just a bigger exhaust valve (1.74 to 1.81, with some proper bowl blending) in a 906 and picked up 12 HP. HP increases were seen from the bottom of the rpm range to the top.
Good point on the ex duration. I suppose the 915 needs help in the ex flow area, so the longer ex duration would be of some benefit.
 
Do your self a favor, make only one change at a time. That Holley intake can spin higher than that. It may be time for some new springs with that cam.
 
What do the cylinder heads flow? Because with a 440 you'll reach peak horsepower around 5000 rpm with 250 cfm and 5400 rpm with 270 cfm.
 
I don't know what the heads flow. I ported them myself with guidelines from Mopar Muscle magazine. And the machine shop opened up the valve throat area below the ex valves. My guess is closer to the 250 CFM range.

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Valve springs are Crane with both inner and outer springs, seat pressures of about 130 #, open pressure is 300 to 320.
 
I ran the Holley Street Dominator intake on my old 440 and it would pull up to 6000 with no problem using 906 heads I ported and the MP .557 cam. It ran a best of 11.49 @ 116 in my 3700 lb 63. Ron
 
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