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is there any way to change duration without changing the cam?

for instance you can change your lift by changing the rocker arm ratio, does this change the duration on the cam also?

the reason I am asking there was a post about cranking compression a few weeks ago and I was reading back through and I post my cranking compression (cold) @ 240-270 psi One guy says that the duration is not long enough. the listed duration for my camshaft is Duration @ .050 259/269 Lift: .644/.643 Lobe Center: 108c solid roller.

engine is a sbf 393 w N/A with a c-4 and a 4500 converter and a dual plane intake. I know I was running a class at the time and it called for the dual plane, looking at a super victor.

So do I need a new cam or just keep on keeping on
 

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Going from a 1.5 to a 1.6 will change duration by about to 2 I think it is 1 degree for ever .5 so if you are 259 @ 50 with a 1.5 you will be 261 @ 50 with a 1.6
 

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Also if you retard the cam timing some it will leave the intake vavle open past BDC a little longer which will help bleed off some compression. not much but some
 

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(cold) @ 240-270 psi One guy says that the duration is not long enough. the listed duration for my camshaft is Duration @ .050 259/269 Lift: .644/.643 Lobe Center: 108c solid roller.
What rpm range do you plan on running?

engine is a sbf 393 w N/A with a c-4 and a 4500 converter and a dual plane intake. I know I was running a class at the time and it called for the dual plane, looking at a super victor.
Depending on the heads and rpm range a Victor Jr. may do much better for you.

You might be able to play with you lash, but it would more than likely take a dyno to measure the difference.

G-
 
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