Split ratio rockers for Vortec heads?
#1
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Split ratio rockers for Vortec heads?
By a mistake I have bought a set of split ratio 1.5/1.6 full roller rockers for my Vortec heads, instead of an 1.5 ratio kit.
Heads are prepared for higher lift, so that's not a problem.
My plan was to change from stamped roller tip 1.6 rockers that I use today to a less Extreme 1,5 full roller rockers.
Engine is an L05 Chevy 350 factory roller Block rebuilt to carb and with T56 manual trans.
Cam:
Lift: .495 / .500, Duration @ .050: 217 / 225, Centerline: 110,
Type: Hydraulic Roller
Duration Exhaust: 278
Duration Intake: 270
Lobe Separation: 114
RPM Range: 1300 to 5500
Will this set up benefit from a split ratio set up, or should I return them?
Heads are prepared for higher lift, so that's not a problem.
My plan was to change from stamped roller tip 1.6 rockers that I use today to a less Extreme 1,5 full roller rockers.
Engine is an L05 Chevy 350 factory roller Block rebuilt to carb and with T56 manual trans.
Cam:
Lift: .495 / .500, Duration @ .050: 217 / 225, Centerline: 110,
Type: Hydraulic Roller
Duration Exhaust: 278
Duration Intake: 270
Lobe Separation: 114
RPM Range: 1300 to 5500
Will this set up benefit from a split ratio set up, or should I return them?
#2
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Re: Split ratio rockers for Vortec heads?
With that cam and those heads, the 1.6 will be of benefit on the exhaust side.
I'd suggest keeping them.
I'd suggest keeping them.
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Re: Split ratio rockers for Vortec heads?
A difference of opinion...
On Vortec heads, the int flow (a) is already significantly "enhanced" compared to the exh side; and (b) doesn't really benefit from increased lift anyway (flow stops increasing above around .500" of lift). But the Vortec exh port has the same poor flow as any other stock SBC head. The best way of improving the imbalance is by increasing the exh duration, to 10° or more greater than the int. But since that cam lacks that feature, increasing the exh lift is the next best way of increasing exh flow a little bit, to more nearly match the improved int flow offered by those heads.
As said, just a matter of opinion.
On Vortec heads, the int flow (a) is already significantly "enhanced" compared to the exh side; and (b) doesn't really benefit from increased lift anyway (flow stops increasing above around .500" of lift). But the Vortec exh port has the same poor flow as any other stock SBC head. The best way of improving the imbalance is by increasing the exh duration, to 10° or more greater than the int. But since that cam lacks that feature, increasing the exh lift is the next best way of increasing exh flow a little bit, to more nearly match the improved int flow offered by those heads.
As said, just a matter of opinion.
#5
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Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
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Re: Split ratio rockers for Vortec heads?
+1 for using on the exhaust valves for the same reasons that Sofa said.
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