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Old 06-16-2012, 10:45 PM   #1
5405spd
 
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Default 540 BBC Flat tappet cam

Is anyone running a 540 with a flat tappet cam? I am going to try a 276 276 at .050 with 318 advertised duration ground on a 110 with .640 lift with a 1.75 rocker. I installed this at 107 ICL. I have 335 AFR heads with 10.5 compression. I made 720 hp with a hydraulic roller and about 690 ft lbs., but it would only go to about 6200 rpm. Is my clay smith flat tappet going to help or not? Thanks.
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Old 06-17-2012, 06:07 AM   #2
want-a-be
 
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Originally Posted by 5405spd View Post
Is anyone running a 540 with a flat tappet cam? I am going to try a 276 276 at .050 with 318 advertised duration ground on a 110 with .640 lift with a 1.75 rocker. I installed this at 107 ICL. I have 335 AFR heads with 10.5 compression. I made 720 hp with a hydraulic roller and about 690 ft lbs., but it would only go to about 6200 rpm. Is my clay smith flat tappet going to help or not? Thanks.
How are you going to use this engine? Racing only? I would consider a little tighter LSA,... maybe 108-106ish. Fuel type? I would consider dropping the intake duration to about 270-272 or so. Lift looks ok. Should rev ok. What RPM are you wanting to hit? Could call Cam-motion and ask for Bob. He can recommend you a pretty good cam.

Don
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Old 06-17-2012, 04:36 PM   #3
5405spd
 
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How are you going to use this engine? Racing only? I would consider a little tighter LSA,... maybe 108-106ish. Fuel type? I would consider dropping the intake duration to about 270-272 or so. Lift looks ok. Should rev ok. What RPM are you wanting to hit? Could call Cam-motion and ask for Bob. He can recommend you a pretty good cam.

Don
This is a pump gas motor. 89 octane with water injection at wide open just to be safe. I wanted 6700 or so with closer to 750 hp. I do like cams ground with a 108 lsa, but I figured a 540 has enough low end torque. The cam we dynoed with was on a 110 and had 696 tq at 4600. I want that moved up in the power band.
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Old 01-06-2013, 03:00 AM   #4
glpg80
 
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This is a pump gas motor. 89 octane with water injection at wide open just to be safe. I wanted 6700 or so with closer to 750 hp. I do like cams ground with a 108 lsa, but I figured a 540 has enough low end torque. The cam we dynoed with was on a 110 and had 696 tq at 4600. I want that moved up in the power band.
Tightening the LSA of a camshaft will increase area under the curve with concentration in midrange torque while removing torque from up top. However a 540 has no lack of torque regardless of the RPM band so this is a bit of a mute point. 106-108 LSA is common where i tend to prefer 108 and having the ability to retard or advance the cam to 106 or 110. A more wide spread LSA will table top peak horsepower for more torque in a particular window, dictated by the duration of the camshaft's IVC event, converter specs, head specs, timing, and other variables of your build. A wider LSA will also extend your top end RPM window a bit to allow you to get more from your heads if there is more to be had and your valvetrain is up to the task. The trade off with a wider LSA is a much less "peaky" horsepower motor.
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