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Would there be anything to gain by changeing to 1.6 rockers vs 1.5 rockers on a mildly modified 406 small block.Current componets are Dart dual plane port matched to GM 462624 heads w/mild bowl work Manley swirl polished S.S.valves,1 5/8 shorty headers,2 in exhaust w/x-over,9.25 to 1 compression,ultradyne 276/286 hyd cam,625cfm street demon carb vac.secondaries and a turbo 400 trans 2200 stall converter.Balanced and blueprinted.Installed in a 3200lb street rod.
 

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Well, I doubt I am telling you anything new, but that will give your valves a bit higher lift. Is it necessary with the cam you now have in there? That is a fairly radical cam, I imagine for about 3500-6500 RPM's, isn't it? Are you OK with the carb you have? Have you thought about a Q-jet carb, even the stocker ones flow about 750 cfm and up, I was wondering if you might be a bit undercarbureted at all?

I would love to hear more about whah you went through working on that 400 block, as I have one I am considering building up. OR, maybe building down into a 372 de-stroker.
 

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With that cam you wouldn't see much, maybe 5-10 HP-maybe. You would be better of buying/building some full length headers for your rod. It will really wake up the engine and let your components work together better, shorty headers are better than factory cast iron but they don't scavenge the cyl properly (because the tuned length is way to short) and with that cam you are not getting your engines full capabilities. I would say that with a full length set of headers you could pick up 25 HP and a lot more midrange torque. Those 1.6 rockers are not worth the money and can screw up your valvetrain geometry, your cam doesn't need them. They do wake up a factory cammed engine nicely though.
 

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WHAT DO THEY COST, LIKE $100? IF YOU WISH YOUR CAM HAD MORE LIFT (MORE HP, LESS LOW END TORQUE) PUT THEM IN. THEY DON'T DO ANYTHING TO THE DURATION JUST LIFT, SO I'VE BEEN TOLD. (BUT HOW SMART WAS THAT GUY?)
 

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The increase ratio rockers will cause your motor to act somewhat as though you had a higher lift cam. The duration does not change, but the lift action speed is increased and the lift is increased from start to finish across the entire lift duration. So there can be benefit for a head/motor that can handle the addititional flow. It is not a substitute for an different cam because the cam grinders are taking lots of other things into consideration. If you decide to do this, be sure that you have enough spring travel to accept the increased lift. You may have to relieve some metal from the base of the spring seat to allow for the additional spring compression in order to avoid coil bind.
 
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