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Discussion Starter #1
Hey Mutant 68...Thanks for the info. I have never been on this site and wanted to see if I got a answer begore I got into this. Let me break it down.............396 30 over compression is 10.5:1, COMP cam 270H 224 degrees and .510 lift. Performer Rpm intake 4.56:1 gears TH400 w/3000 stall. Valves adjusted 1/2 turn from Zero lash. Ignition is as stock points distributor w/ Mallory conversion electronic ignition kit, vacuum advance. Mallory Pro master coil and a MSD 6a box timinng set at 26 degrees advanced. Carb is a Holly 700 double pumper changed needle and seat, adjusted floats, tighted up accelerator pumps, no play. Not sure if I should change pump cams or not. Idle feed seems to be O.K. As you read this I am going to reset timimg at around 36 degrees and reset carb and see what happens. The list of things you gave me seems like good info. I'll check these things out, and let you know what happens. If my stats on the car help you out any more or give you moe insight ....let me know. Oh yeah.... thanks motorhead!!

[This message has been edited by Atth2o (edited 11-11-2000).]
 

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Give us some more specifics on your combo.What are you running?Cam(give speck's),compression ratio,intake,gear,trans,stall speed?
The reason I ask this is to tight of a converter,or to high of a gear and the motor will not like a double pumper.

First off,make sure you don't have a vacuum leak!Reset your valves(1/4-1/2 turn down from zero lash for hydraulics).

You should work with your distributors advance curve first when tuning.You can not setup the carb properly if the timing is not right.YOU WILL NEED A DIAL BACK LIGHT FOR THIS TASK!!!

Set your timing at 36 degrees of full advance(when you observ it stop advancing)with the vacuum advance disconnected and plugged.If it stops advancing above 3000 RPM you need lighter advance springs.Put some springs in it to acheve full advance at around 2800-3000.

Are you running vacuum advance?If yes, than try hooking it up to manifold vacuum.If it starts pinging get a canister with less advance(8 degrees),or get an adjustable one.

You say you are not running vacuum advance,here's something to think about.
What is your initial timing?10 degrees?Many times an off idle stumble will magically disapear with slightly more initial advance,something like 14-18 degrees might just do the trick.This means you will have to install a larger advance stop bushing to reduce the advance.A BB usually likes around 36 total.Try to limit the distributors advance to about 22 degrees.If you have a very radicl cam and somewhat low compression(for the cam)you may want to run about 20 degrees.
I prefer to use MSD distributors because they limit the advance just like a factory unit.The Mallory unit requires you to bend a pin.This seems kinda hokey to me.I haven't seen the Pertronix unit so I don't know what to say about them.

Next work on your carb.Here's a list of things to do.If it looks grungey,give it a rebuild.Make shure the idle feed passages at the top of the carb are not plugged.Give them a shot of carb cleaner.Remoove the idle feed mixture screws and give the holes a shot of cleaner as well.Adjust the float level.Set your powervalves and jet it in.Make shure there is no play inbetween the acellerator pump cam and the lever that depreses the pump diaphram.Tune your accelerator pump squirters,now tune your accelerator pump cams.

If none of this works don't call me




[This message has been edited by mutant 68 (edited 11-12-2000).]
 

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Excellent tips mutant - one question though, did your car ever run good off the line? That would help answer a lot of mutants questions. If your car ever ran good off the line then accelerator pumps are suspect. Make sure they aren't leaking at all, and are providing a good squirt into the carb.

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Discussion Starter #5
I changed the intake, carb and new set of sanderson headers, and put the MSD box on the car after running a long time. Car was wicked off the line. After this change from stock iron madifold edelbrock stock replacement quadro-jet and stock exhaust manifolds I have this problem. Not much of a stumble just enough to **** you off. The car is fast mid 12's no monster or anything. Your probable right about the vacuum leak,it makes sense but I can't find the friking thing!!!!! <BLOCKQUOTE>quote:</font><HR>Originally posted by houndog72:
Excellent tips mutant - one question though, did your car ever run good off the line? That would help answer a lot of mutants questions. If your car ever ran good off the line then accelerator pumps are suspect. Make sure they aren't leaking at all, and are providing a good squirt into the carb.

<HR></BLOCKQUOTE>
 

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Discussion Starter #6
Did you get the info on the car?
<BLOCKQUOTE>quote:</font><HR>Originally posted by Atth2o:
I changed the intake, carb and new set of sanderson headers, and put the MSD box on the car after running a long time. Car was wicked off the line. After this change from stock iron madifold edelbrock stock replacement quadro-jet and stock exhaust manifolds I have this problem. Not much of a stumble just enough to **** you off. The car is fast mid 12's no monster or anything. Your probable right about the vacuum leak,it makes sense but I can't find the friking thing!!!!! <HR></BLOCKQUOTE>
 

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That rules out your stall & gears as being culprit.I don't think you have too mutch CFM for your combination either.
You mention you have 26 degrees of advance.Is that what is in the distributor, or is this total?You said your distributor is stock except for the conversion.I thought stock points distributors had 28 degrees of advance built in.You didn't make that very clear.
You need to set your timing at full advance(when your advance mechinism quits advancing)with vacuum disconected and plugged.Then (with vacuum advance still disconected and plugged)take a reading of what you have for initial.Write both of these down.You will need to know this for further reference.
While you are dealing with the distributor check out how much advance the vacuum canister has.This should be stamped into the arm on the canister.If not,hook it up to manifold vacuum(where it should be with todays crappy fuels) and observe how much it advances with your timing light.Keep this on record too.



[This message has been edited by mutant 68 (edited 11-12-2000).]
 

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Discussion Starter #9
Hey...
Winters....ok. I am in a camaro club based in Sacramento, Camaro Generations (www.camarogenerations.com) check out the site and see what you think, if you are interested in more e-mail me back and i'll give you my number and we can discuss more....o.k. <BLOCKQUOTE>quote:</font><HR>Originally posted by tireblazin68:
hey,
Your in Vacaville?? My dad might know you, he grew up there, his name is Tim Walters, we live in Winters now.
<HR></BLOCKQUOTE>
 
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