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Discussion Starter #1
hello,help! 350 chevy .40 over, dualplane highrise manifold,pertonix distrib.,10:1 compression,.530 lift,292 duration,[roller cam/rockers,750 holley,msd wires,headers,phew! has wet plug on one cylinder,black on others,revs in park, falls on face when in geaf off idle,hard to keep running even in park,timing set at 36 degrees total,stuff new!compression tested on wet cylinder 165 psi. others 155,170,180,180,,too cold outside too check last three.should compression test be done on warm engine?do readings change?whats wrong

[ March 04, 2002: Message edited by: jimm ]</p>
 

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Sounds a bit strange, most true highrise manifolds are single plane not dual plane(makes a difference). If you remove the carb you can tell for sure. You've got a monster cam but no mention of any head work to handle the added lift. One wet plug, gas or oil. Could be you simply damaged a valve seal. Where's your base timing set? If you're running that much cam with what might be a single plane manifold you're going to have to run that idle pretty high, get your base timing right, and consider a manual trans or a good stall converter to keep her from loading up while stopped for lights.

[ March 03, 2002: Message edited by: dmorris1200 ]</p>
 

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Discussion Starter #3
thanks for input dmorris!heads are double hump 2.02/1.60 mild port gasket matched.springs to match cam,can you explain base timing please?also, what about compression values and method of testing?thanks again!
 

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the intake m,anifold is dual plane[medium rise?what about vacumn?leaking booster?where does vacumn line from distrib. hook to holley 750 [mech. secondaries]when i said booster i meant brake booster.thanks again folks,just plain ol dumb jimm.
 

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What's up jimm, base timing is critical. Not enough can make her hesitate, too much can do some internal damage. I'm a Ford guy but I would think finding base timing for your car shouldn't be too hard(maybe some Chevy guys will chime in). Then mark your balancer and aim your timing light. If you have a vacuum advance disconnect it. Also with a lot of cam it's better to idle her a little high. A long duration cam causes dynamic compression to drop due to valve overlap. There's less time for each cylinder to build compression if both valves are open while the piston is coming up. Most noticable at low r.p.m.'s this also causes erratic vacuum at idle, which in turn causes the fuel to atomize poorly. So try playing with the idle, I don't know where your's is set. And make sure your floats are adjusted right and idle air/fuel mixture. Probably wrote too much but just trying to help.
 

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just read your latest post, on my Ford distributor vacuum goes to a ported vacuum on carb. No vacuum at idle but off idle you'll get vacuum. If Chevy set-up is different somebody let us know. Also don't forget to keep an eye on that fouled plug.
 

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Discussion Starter #8
mr. morris, accent on the mister,! thanks again for the input. no way too much until figured out.back at you later. jimm
 

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Your initial timing is what you set with your timing light,with vacume advance unhooked. Your total is the max amount of timing to your engine including vacume advance and mechanical at what ever rpm its set up for. If you are sure you are getting 36 total I would think your initial is close.Check float settings to be sure its not flooding. Also you haven't said what plugs you are using, they may be to cold and fouling.You said everything is new, how many miles on it?
 

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Hay guys I heard holley if the engine backfired just one time it could have blown a power valve and be flooding.Blown power valves don't let you see the flooding like a floot would. ROY
 

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if this guy was flooding more than one plug would show it. He said he had only one wet one, probably oil. If he's only getting a stumble off idle it's doughtful it's a blown power valve. Everyone I've talked to said a blown power valve will give you a serious flooding problem.

[ March 04, 2002: Message edited by: dmorris1200 ]</p>
 

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Discussion Starter #12
dmorris,roynewton,liquidlarry,guys,i hate to own up to it,but it wouldnt be fair to you. my dumbness runs deeper than dirt!iwas putting taper seat plugs in double hump heads!!!couldnt hear the leak around the plugs because i only have headers on. thanks a million for your taking the time to worry with my problem.dmorris,idle was too low as you suggested.man,this thing rips!hope ican help someone in future like you all helped me.jimm [probably be distant future]
 

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Hey jimm, thanks for the update. Always like to here how things end up. We all have a few 'oops' in our history. Rip up a little blacktop for me!
 

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Everyone makes mistakes, even me, and I'm perfect. Okay, so I'm not perfect- I drove my car around for a week with it running like crap, lost to everything even at WOT, and all it was was that in the fall when I checked my plugs I had no anti-seize, so I lightly installed the plugs, and they got loose. Go me.
 
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