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Old 04-15-2010, 10:25 PM
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How can I get better throttle response?

Hi my name is Joseph and I have a 406 small block chevy and I was wondering if I could get some advice on how to get better throttle response. I am running a 750 Holley with vacume secondary's and victor jr open plenum manifold, and 210 cc AFR heads. I have 76 size jets in the primary's and 80's in the secondary's. I am runnng I believe a size 28 squirter but not positive. I have the timing set at 32 degrees total. I am new to this and I am trying to learn I have an assortment of cams, squiters, jets, and springs I am loookin for some advice to what I should do to get a better throttle response when I crack the thorrtle.

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Old 04-16-2010, 03:01 AM
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What is your specific problem with the throttle response?? Does it stumble?? Cough or backfire?? Just slow acceleration??

What is the initial timing??

What size and type of cam is in the engine??

You may well need a bigger shooter and possibly a bigger pump cam.
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Old 04-16-2010, 09:26 AM
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x2 what cam is in it
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Old 04-16-2010, 09:43 AM
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If you have a wide overlap cam, you will get a smoother idle but will get a slower response. With a narrow overlapping time cam you will get a quicker respond at a cost of rough idle. A higher compression motor will make it rev quicker.
Your timing is a little low. It should be closer to 38* to 40*.
Adding lighter advance springs in the distributer will make it rev quicker.

Last edited by lg1969; 04-16-2010 at 09:55 AM.
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Old 04-16-2010, 07:14 PM
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The engine makes good power and when you go to give it gas there is no real hesitation but when the engine is idling in park and I go to rev the engine it does not seem to rev up quickly, it is like somthing is holding it back. The thing with this engine is that I bought it through a guy in a hot rod club for a great price. Before I bought the engine I asked for a build sheet and he said he had one but could not find it but knew he had it so I took his word and bought the engine and since then I still have not got a build sheet which kinda bums me out becuase to find out what the cam is I need to take it out. What I can describe about the cam is that it is very chippy the guy did tell me that the engine needed to idle around 900 rpms and that I needed a 2800 stall which is what i have and it works great. I do not have a backfire trough the carb or anyting it does not stumble when your driving it is smooth all the way through. The acceleration when you rev the car up does not seem as snappy as it should. But then it could be just the characteristic of the engine.
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Old 04-16-2010, 07:26 PM
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Compression check. First thing I would do. Since you'll have the plugs out, check TDC on #1 compared to timing marks on the balancer. Whenever I get a so-called "built" engine from someone, I'll always break it down first. Once the engine's installed and running, it'll be a pain to pull it and break it down. So might as well do it in the first place.

P.S. I built a 406 with camelbacks and a crower solid cam, edelbrock performer RPM and a Holley 750 DP. The carb. worked perfect out of the box. You might want to try setting your carb. back to out-of-box settings (jets, pumps, cams, everything). A lot of times if you choose the right carb (new) for that particular engine, out-of-box usually works pretty well. Oh, and the throttle response was snappy...partially because of the solid-cam, of course.
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Old 04-16-2010, 07:39 PM
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The cam that is in the engine is a solid roller lifter cam and i have lifters set at 24 thousandths all the way around because of not knowing what the specs are. I can hear them clacking so I know they are not tight.
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Old 04-16-2010, 07:45 PM
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Subscribed. I just finished building a 406 that does the same thing.
Holley Street Avenger 770, Comp cams 278 roller cam, cast Vortec heads.

Not sure where to start.
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Old 03-30-2012, 07:37 PM
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if its an automatic car id say you would get better throttle response from a 670 carb just my 2 cents i know its an old thread but some people might look here for advice
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Old 03-31-2012, 08:35 AM
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Quote:
Originally Posted by BigChevyFTW
if its an automatic car id say you would get better throttle response from a 670 carb just my 2 cents i know its an old thread but some people might look here for advice
Ayuh,... This thread is 'bout 2 Years old.....
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