Need Carb Tuning Advice Again 8896 Holley 1050

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Re: Need Carb Tuning Advice Again 8896 Holley 1050

Post  512Fairlane on October 9th 2010, 8:33 pm

Thanks again for the input. Lem gave me a call and straightened me out even more. I jumped to .089" bleeds and it really smoothed it out in the burn out. The throttle response continues to improve. I went 1.457 60 ft, 6.578 @ 103.44 mph, 8.619, 10.350 @ 130.13 with the .086" bleeds. After switching to the .089" it slowed some to 1.474, 6.626 @ 103.48, 10.436 @ 128.33. The air went south between the 2 runs and everyone else I talked to slowed around the same amount. We get 1 time trial in the morning so I'm not going to change anything. After talking with Lem I may be ready for some more main jet if my mph doesn't come back. I might be imagining things but the throttle response has seemed to really make my reaction times better and more consistent. I had a .000, a .006 and a .026. Hopefully we can go some rounds tomorrow. Thanks.
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Sunday update

Post  512Fairlane on October 10th 2010, 8:13 pm

They switched the program to 1/8 mile today and we got one time trial. Went 1.468 60ft. 6.593 at 103.58 on the time trial. According to my gages the air pressure, temp. and humidity were all very close to when I ran yesterday morning (6.578 at 103.44) so I'm still in the ball park. Throttle response didn't seem as good this morning for some reason and my lights went to crap .093 time trial and .101 first round. First round it went a 1.505 60 ft and a 6.651 at 103.60 1/8th mile. The temperature went up 20 degrees and the pressure dropped .45 inches so some of this could have been air or bad starting line. There is a test and tune at the end of the month that I may play around with it some more. May be last race ever at Gateway. Sad
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Re: Need Carb Tuning Advice Again 8896 Holley 1050

Post  cantedvalveFord400 on September 28th 2015, 7:27 am

this is an old thread, I'm compelled to revive it, cuz there's a lot of these 2-circuit vs. 3 circuit questions on the net. very rarely are they ironed out. first a bit of history...

IIRC the 8896 is another old 3-circuit carb design.
by what racers tell me the 9375 was the best out of box tuned Holley 3-circuit Dominator made, the others all had major problems when trying to run the 3-circuit in a single-4 application

Holley developed the 3-circuit Dominator around 1970. they copied what was at the time, the Mopar 383-440 emission metering blocks, which were 3 circuit. keep that in mind, because that's why these carbs are so lean at WOT. often the timeslips don't improve with jet changes, or even when the jets are removed completely.

these blocks have the idle feed restriction tube, pressed into the main wells, if you remove the main jets, you can see the bottoms of the tubes inside behind the jets.

this carb design was originally released in Dominator form, as the list 6214 and 6464 carbs. if you find an old copy of the Holley carbs manual copyright 1976, they are both covered there.

now the critical point- both carbs were designed NEVER to be used in a single 4 barrel application. they were designed as a dual-4 barrel only application, where the available vacuum signal would be split in half between 2 carbs, and 8 barrels.

with less available signal, they were calibrated very rich at idle/part throttle, and a 3rd intermediate circuit added, to provide enough fuel to cover the weaker signal using 2 carbs.

the 6214 was designed to be used on an IR independent runner manifold, 2-4 setup, and 1150 cfm per carb, and specifically designed to dampen fuel "standoff", a cloud of fuel mist that forms above the carbs on an IR setup. It was used on Ford small block 302, with one barrel per cylinder, no plenum. also with a plenum later, where the carbs had to be jetted up the larger the plenum size.

the 6464 was designed to be used on larger engines with a tunnel ram, 2-4's, and plenum and was 1050 cfm each carb.

again, NEITHER carb was ever designed to be used in a single 4 bbl. application, and the Holley manual specifically states that many times.

fast forward, the later 9375 and 9377, 1050 and 1150 Dominator carbs, are direct descendants of the 6214 and 6464, with all the related foibles of being 3-circuit carbs.

I ran a 3 circuit 1150, 9377. I was given 2 of them for free, from 2 separate people. the problem with them is this- if you try to run them on the street or bracket car with 1-4 bbl, the idle and part throttle is pig rich. the top end is lean.

reason being the idle transfer slot is very long, and intermediate comes in and makes it even rich- so idle/part throttle is pig rich. then at WOT, the idle feed restriction tubes in the main jet wells, restricts WOT flow, and leans WOT out.

these carbs can be lean at WOT even with the jets removed. and jetting down to try to clean up the idle/midrange, makes the WOT even leaner yet. the much stronger signal of any engine with only ONE CARB, throws the calibration of these dedicated 2-4 tunnel ram carbs, out the window. there's just too much signal at idle/part throttle and it's always rich. with only one carb, it's always going to be lean at WOT too.

the fix is, open up the idle air bleeds, and intermediate air bleeds, a dramatic amount. and replace and reduce the diameter of the main air bleeds. not hard to do, but time consuming.

or, change the metering blocks to conventional Holley 2 circuit, and do away with the intermediate circuit altogether.

a few have gotten decent street drive-ability by just plugging the intermediate circuit, and running it on the idle and main circuits only.

these carbs have no power valves, the pv is factor blocked with casting, and there are no pv channel restrictions drilled in the blocks. the intermediate system feeds by a pair of drilled restrictions in the front of each metering block.

Holley made metering block kits 85r-5230, that took a power valve, and put more fuel into the engine at WOT, but stated it still put less fuel in the engine than a dedicated 1-4 Dominator.

so there you have it.

having said that, there's a lot of these carbs around, and if you want to tinker, you can pick up a Dominator on the cheap, and convert it, and have a low buck racing carb.

it needs the metering blocks, and air bleeds dialed in, per application, for a single 4 app.

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