camshaft for mild 340
Scroll to the bottom of the above linked page.
What I like about this is the in general build perameters, except the missing duration @ .050, and it's reasonable power output while maintaining good drive abilty with the wider centerline cams.
Thisis good everyday streeter tips.
Scroll to the bottom of the above linked page.
What I like about this is the in general build perameters, except the missing duration @ .050, and it's reasonable power output while maintaining good drive abilty with the wider centerline cams.
Thisis good everyday streeter tips.
Computer simulations show what happens when we increase compression, add duration in different combinations and then adjust lobe centers using a hypothetical Chevrolet 350 engine assembled with different combinations of compression, camshafts and valve timing as a base.
Stage 1 Base Engine Analysis
Typical low performance: Standard 1.94 and 1.50 valves with typical port flow, OE dual plane 4bbl intake, OE exhaust manifolds and single exhaust.
Static Compression Intake Duration Exhaust Duration Lobe Centers
Fuel
Stage 2
8.25:1
250 Degrees 260 Degrees 110 Degrees 87 Octane
Volumetric Efficiency Torque/RPM
HP/RPM
Effective Compression Vacuum
Analysis
86.7% 360/3,000 245/4000 7.13:1 20.9 in/Hg
Mild production performance: Standard 1.94 and 1.50 valves with typical port flow, OE dual plane 4bbl intake, OE exhaust manifolds and dual exhaust.
Static Compression Intake Duration Exhaust Duration Lobe Centers
Fuel
Stage 3
9.25:1
260 Degrees 270 Degrees 112 Degrees 87 Octane
Volumetric Efficiency Torque/RPM
HP/RPM
Effective Compression Vacuum
Analysis
87.2% 373/3,000 268/4,500 7.61:1 21.1 in/Hg
Performance engine: Larger 2.02 and 1.60 valves and mild porting, single plane aftermarket intake and 1-5/8 x 36 in. headers with low restriction mufflers. With the increased effective compression and volumetric efficiency, premium fuel is recommended.
Static Compression Intake Duration Exhaust Duration Lobe Centers
Fuel
10.0:1
288 Degrees 288 Degrees 114 Degrees 91 Octane
Volumetric Efficiency Torque/RPM
HP/RPM
Effective Compression Vacuum
94.8% 404/4,500 372/5,500 7.55:1 19.6 in/Hg
NOTE — In all but the last stage, “dual pattern” camshafts with increased exhaust duration were required to achieve 75 percent or better exhaust flow relative to intake. Also, note vacuum was kept within a range of 1.4 in/Hg for all three engines. (Ithink there talking about wide open throttle vacuum readings here.)