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Carb tuneup for 622 tunnel ram combo?
http://motorsportsvillage.com/forum/viewtopic.php?f=6&t=9939
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Author:  mslayton [ Sun Feb 03, 2013 9:05 am ]
Post subject:  Carb tuneup for 622 tunnel ram combo?

My buddy put a sheet metal intake and a pair of old 8896 non-HP dominators on his Top Sportsman corvette last year and we struggled the whole season with the tune up because of the lack of adjustability. I think the typical 3 circuit issues caused us real problems with blackening plugs and not coming up cleanly on the converter. We have a two 9377 Quickfuel dominators that I'm going to map and use this season, but I've never worked on a dual carb application and I'm looking for suggestions for a starting point. I dont have all the engine details, but the motor is a 622 bbc with 12 degree profiler heads that we ran a best of 4.79 at 147 and 7.45 at 183. This was all motor using VP c-16. It's a powerglide with 4.30 rear gears and 33.5 x 16.5 rear tires. The car is equipped with a fogger system, but we've never used it because we want to optimize the tuneup first.

My hope is that we'll have a Racepak on the car this year so we can tune with some data.

Any suggestions would be appreciated. I've insisted that we could do this ourselves and save the funds he wants to spend buying two carbsdollars for the investment into a Racepak. I've learned a ton on this board the past few years and have done both a gas and E85 two circuit conversion, so I'm hoping some if that knowledge can be used to build these carbs.

Thanks in advance for any help/suggestions.

Author:  jmarkaudio [ Sun Feb 03, 2013 10:02 am ]
Post subject:  Re: Carb tuneup for 622 tunnel ram combo?

Check out Tuners response on this thread, it will be a starting point if you change them to 2 circuit. The biggest change is in the idle and transition metering, and t-slots need to be covered at idle.

viewtopic.php?f=6&t=6820

Author:  mslayton [ Sun Feb 03, 2013 11:02 am ]
Post subject:  Re: Carb tuneup for 622 tunnel ram combo?

Thanks Mark, good info there. My buddy is old school, so I'm working on him to allow me to do the 2 circuit conversion. With the existing 3 circuit blocks, so you have any idea if they would have the same fuel delivery issues from the mains given there would be two carbs? I was considering just plugging the intermediate circuit and tuning it like a 2 circuit conversion, but don't want to be chasing a lean condition.

Author:  jmarkaudio [ Sun Feb 03, 2013 11:16 am ]
Post subject:  Re: Carb tuneup for 622 tunnel ram combo?

Not likely with C16 and 2 carbs, the only issue with the carbs is the later Dominators have the idle feed up high. Early ones pinch the tube at the bottom. Thread the intermediate jet, you can start with them plugged and add a little if needed. The idle circuit needs some work, smaller jets AND bleeds to tailor the fuel leaner at idle, yet have enough duration on the transition circuit.

Author:  mslayton [ Sun Feb 03, 2013 1:18 pm ]
Post subject:  Re: Carb tuneup for 622 tunnel ram combo?

Thanks Mark .

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