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SBC Cam Questions
I’m considering upgrading the cam in my 383 stroker engine, and I’m stuck between two cams. The current cam is a Comp XM-262-H #12-236-3. This is a flat tappet cam. The ones I’m looking at are both hydraulic roller cams by Comp. XR-276HR-10 #12-423-8, and XM-276HR-12 #12-418-8. These cams seem to be virtually identical with the exception of lobe separation angle My questions are: How different would either cam make the engine run?
What advantage/disadvantage would I see with either cam?, And Which cam would be less prone to reversion? Currently the engine has stock style cast iron heads with port work, 9.5:1 compression, a cast iron high rise intake manifold, and stock style center rise exhaust manifolds. In his book, Dennis Moore recommends the XR-276HR-10 cam. Any comments would be most welcome. Camshaft Specification Table Part Number 12-423-8 Engine 1955-1998 Chevrolet262ci-400ci8cyl. Grind Number CS XR276HR-10 Description Intake Exhaust Valve Adjustment 0 0 Gross Valve Lift 0.502 0.51 Duration At 0.006 Tappet Lift 276 282 Valve Timing At 0.006 Open Close Intake 32 64 Exhaust 75 27 These Specs Are For The Cam Installed At 106 Intake CL Intake Exhaust Duration At 0.05 224 230 Lobe Lift 0.335 0.34 Lobe Separation 110 Recommended Valve Springs 986-16 ---------------------------------------------------------- Part Number 12-418-8 Engine 1955-1998 Chevrolet262ci-400ci8cyl. Grind Number CS XM 276HR-12 Description Intake Exhaust Valve Adjustment 0 0 Gross Valve Lift 0.503 0.51 Duration At 0.006 Tappet Lift 276 282 Valve Timing At 0.006 Open Close Intake 28 68 Exhaust 75 27 These Specs Are For The Cam Installed At 110 Intake CL Intake Exhaust Duration At 0.05 224 230 Lobe Lift 0.335 0.34 Lobe Separation 112 Recommended Valve Springs 986-16 |
Re: SBC Cam Questions
No one has any input???
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Re: SBC Cam Questions
I am running the XM270HR in my SBC 400. It has a nice lope to it and will idle at 750 rpm which is important with an Alpha 1 outdrive. I'm turning a 14 1/4 x 20 screw at 5400rpm which is good for 60 mph. This is in a 20 footer that weighs in over 4000lbs.
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