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Discussion Starter · #1 ·
I bought a truck recently from a friend. All I know about the engine is that is that it was dynoed at 450 hp with 10.5:1 compression, 292 duration cam (radical idle), msd billet distributer, msd 6al box, blaster 3 coil, 650 holley double pumper, holley single plane high rise. It doesn't miss a beat if i rev with just primaries but if wide open when secondaries open it studders. Also just recently it wants to rev and almost die while idling i.e. jump from 1200 to little to nothing. I have replaced the timing chain, could this be my cam? Timing? Carb?
 

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Discussion Starter · #2 ·
I checked my vacuum it jumps from about 4 to 7. I put a 3.5 power valve in it. Is this too big, too small? I have 70 jets in front and 76 in rear. Put new accel plugs and msd wires on it. Can't figure out where my problem is. Can anyone help
 

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Also, whenever I have put a vacuum gauge on it was pretty steady unless my idle mixture screws were out of adjustment. Also, the whole rpm fluctuating at idle is something else my truck did when the idle circuit was to lean. As far as the secondaries go, I've always been told that they won't work right until you have everything else right. Get it tuned with the primarys alone first then move on.
 

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Discussion Starter · #7 ·
Noticed that while under hood looking down carb the primarys are very responsive but its when the secondaries open it bogs. It doesn't seem like the secondaries shoot a strong stream of fuel like primary does. Again this is a 650 holley dp 4150 series. Any help would be appreciated.
 
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