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Discussion Starter · #1 ·
Just bolted a new HP1000 onto my 496. Holy cow is that a great carb. Right out of the box, it runs great. However, I DO have a HUGE bog when I stand on the throttle to launch the car. I was able to improve it a little by setting the idle mixture screws a bit richer. This adjustment lessened the bog when I crack the throttle in park, but under a load (i.e. launching the car) it still falls right on it's face. Also setting the idle screws richer forced me to open up the primary idle speed screw to bring the idle back up. I have a feeling I'm headed in the wrong direction with this approach.

Here's what I plan to do tomorrow. I would like to know from some of you if this sounds like the correct approach:

- Adjust idle mixture screws for leanest possible mixture that will yield the highest possible idle speed without having to crank up the primary idle speed screw.

- try larger primary pump squirters. Stock size is .031. I was going to go to the speed shop and pick up a .033 and a .035.

Other than the bog, this carb runs incredible in every other way. I would appreciate any opinions on this. Thank You.
 

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Increasing your squirter size should do it. My car was tuned good, it had no bog whatsoever but would always spin off the line. I finally got it to hook and sure enough it had a slight bog on the launch. I increased the squirters and it went away.

I don't know what what your ignition is set at but you may want to increase the initial advance also. I think mine is set at 22 initial and 36 total.
 

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- Adjust idle mixture screws for leanest possible mixture that will yield the highest possible idle speed without having to crank up the primary idle speed screw.

- try larger primary pump squirters. Stock size is .031. I was going to go to the speed shop and pick up a .033 and a .035.

Other than the bog, this carb runs incredible in every other way. I would appreciate any opinions on this. Thank You.
Bigger squirters pump the same amount of fuel but over a shorter time, as the exact oppisite for smaller squirters, they shoot the same amount but over a longer time.
The shot size is determined by the accelerator pump (30cc or 50cc).

Now, if you bog on launch go bigger on squirter, if you go then bog go smaller. Also cam adjustments/swaps may help fine tune things.
 

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Is this a stick car? It sounds like you are having a flat spot in the accelerator pump shot. Try going up and see if it gets better or worse. It's possible that it could be shooting too fast also. Does it have 30 cc or 50cc pumps? On my 850 I had to go to a 30 cc rear pump to keep it from loading up before hitting the rev limiter.
 

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Discussion Starter · #5 ·
Thank you all for the responses. It's an automatic with a 10" converter that flashes at 3800. Total timing is 36 -- can't remember offhand what the initial timing is.

The bog is right up front -- instantly. I just picked up some larger squirters so I'm going to try that.

Thank You.
 

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I would try the larger .035 squirter in the rear first . See if it goes away , if it doesn't go put the .033 in the front. If it is still there you might have to purchase a 50 cc kit for the rear. I am sure you will have it with the bigger squirters in there. The main problem is you have a big car , tight converter , and now a huge carb in which the main circuit will come in alot slower .

Dave
 

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Discussion Starter · #7 ·
Dave, I hear what you're saying about the heavy car, tight converter and huge carb -- makes sense. I put a .035 squirter in front this evening, and of course it's 40 degrees and raining. I lit it up in my garage and cracked the throttle a few times. Can't really tell much with the air temp at 40 degrees and no load on the car. Also, with 3" pipes and dumps before the axle it fills my entire house with fumes -- And my neighbors don't share my fondness for cackly big block chevy's. Hopefully the weather will clear up tomorrow so I can drive it. Thanks again for the help.
 
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