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Discussion Starter · #1 ·
Just a general question. what causes the "loping" sound of a cam.
Below are two cams, wich one will cause more of a loping sound and why.

lift
duration
lobe seperation

Basic Operating RPM Range: 2,500-6,000 RPM
Intake Duration 050 inch Lift: 228
Exhaust Duration 050 inch Lift: 238
Duration at 050 inch Lift: 228 int./238 exh.
Advertised Intake Duration: 290
Advertised Exhaust Duration: 300
Advertised Duration: 290 int./300 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.590
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.614
Valve Lift with Factory Rocker Arm Ratio: 0.590 int./0.614 exh. lift
Lobe Separation (degrees): 114


Product Line: Crane Racing Camshafts
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 3,500-7,000 RPM
Intake Duration 050 inch Lift: 248
Exhaust Duration 050 inch Lift: 248
Duration at 050 inch Lift: 248 int./248 exh.
Advertised Intake Duration: 304
Advertised Exhaust Duration: 304
Advertised Duration: 304 int./304 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.599
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.599
Valve Lift with Factory Rocker Arm Ratio: 0.599 int./0.599 exh. lift
Lobe Separation (degrees): 108
 

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Duration and lift affect that "loping" sound, what it really means is that exhaust and intake will be partially open at the same time....you dont really want to much "lope" unless you run a high compression - high RPM engine. You will waste energy and performance in a mild 5.0

Id choose the first cam in the list.
 

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Discussion Starter · #3 ·
I'm actually building a weekend poser car. I am putting a 460 in an immaculate 94 mustang. I am rebuilding the total motor and heads. I will be installing heavy duty springs to except a large cam. I am also sticking with a hydraulic cam. Raptor, from what I understand the smaller the LSA the more overlap you have therefore the first cam above has a LSA of 114 and the second one has 108 LSA. I guess my question is, theoretically even though cam 1 has a higher lift but also has a larger LSA therefore cam 2 with a smaller lift and LSA, would sound about the same.
 

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As GTRaptor describes, the "loping" sound is a characteristic caused by the time both I&E valves are open, the overlap (OVL). For the two cams listed, Cam #1 has an OVL of 67° and Cam #2 has 88°. Cam #1 would sound a little rougher than a FRPP X-303 (OVL=60°) and #2 like a monster. GL and have fun.

 
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