I was posting a lot last week, Ive made some progress since then-

My holley 6221-2 2300 series carb that was giving me headaches turned out to be an inverse idle circuit carb- there is little info on tuning these properly, and even after I rebuilt it it seemed to drip fuel more than spray it.

I bought a new holley 350cfm 2300 series with manual choke and put it on. After doing research on here about jet sizes- people like 54- 61 with most aligning behind a 56 or 61- I found that the carb comes with 61 jets. I left them on, along with the stock acc. cam.

I got the engine with a single header that dumps into a 3" collector and it came with a 3" pipe to a magnaflow muffler, then 3" out the back. I knew it was too big, but I thought maybe the setup was dialed in so I put it on. It turns out that this setup needs some tuning, so today I went and spent too much at a Meineke to have the pipe stepped down to 2 1/2" with a flowmaster 40 series.

I was hoping that my problems with high idle/ low idle in drive with brake on might be helped with a little less silly exhaust system, but it isn't too much quieter or more torquey.

The motor seems to run out around 3000ish at more than half throttle- Im guessing lean, but I don't know- it sounds good accellerating up to there then seems to stutter a little bit

Also it is wanting to die when I stab the throttle from idle. I'm guessing too rich of a shot from the acc. pump cam. It takes off nicely once it is rolling around 1500rpm

I set the timing at 600rpm in Drive with the advance line pinched off and the brake set at around 4 degrees btdc.

I still am having trouble getting the car to idle smoothly when I first come to a stop. At first it wants to die, so if I use two feet to drive I can poke it gently to keep it alive and then it settles into idle at 500-750 rpm. It is a little smoother than before I changed the carb/ exhaust. Any suggestions? I think if I had a manual trans all these issues would be inconviences instead of drivability issues, but thats got to wait until summer.

I hope that however this engine is set up, it hasn't moved the power band so far up the rpms that the stock torque converter is useless- I am having to idle it around 1500 to get it to reluctantly idle in Drive at at stop, and it bangs a little when put in gear!


any suggestions from people with similar setups are like gold to me! Especially if someone has encountered the same problems

Kevin

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madam im adam

I would check for a vacuum leak. The idle jets may also not have been set right. While a 3" exhaust system may have been tad bit on the to big side, it would not effect idle quality.

Running out of steam at 3000 rpms could be caused by a lot of thinks.
Why my poor ole engine doesn't go to much higher then that, but it has 250,000 miles on it.

How are the valve springs? What type of cam are you running? What is the total ignition advance? How good is the fuel pump?

A doubt that a Holley 350 is running lean. They are usually jetted rich.

I would like to advise more base timing. Try 10* BTDC with the vacuum line removed & plugged.

Mike

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Recognized by US Federal Courts as a Fuel Economy Expert!