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 Help with 1050 2 circuit conversion 
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Joined: Sun Jul 31, 2016 9:03 pm
Posts: 2
Hoping Mark can help me out

I have read the conversion many times and decided to do it. I have a 9375 (1050) and completed the job over the weekend. I need some input as I can’t seem to get the car to idle without having transition slot opened about .187 which I know is way too much and tried everything from ½ turn to 2 turns on mixture screws to no avail. It really seems to want to have better throttle response but I think with your help I can get it fixed up- I may need to change bleeds but not sure which way to go for baseline. Here is how my converted carb is currently setup

· #1 and 3 plugged on 34-105 Quick fuel plates

· Kill .026

· IFR .039-moved to lower spot

· .159 Angle Channel

· T Slot Jet .052

· IAB .070

· MAB .026

· 90 Front and 91 Rear jet no PV

· Replaced boosters with .500 12 hole billet

· Cleaned up venturi-removed rough edges and polished

I also cleaned and powder coated the carb and changed throttle plates so everything is fresh. Here is some car info to help out.

· 385 Chevy 3.750 X 4.040

· Mahle Pistons (13.5 comp)

· MSD Crank Trigger-36 degrees

· Comp Cams Cam & 818 lifters

o Int- .706 Lift 273 @ 50 306 total

o Ehx-.676.Lift 286 @ 50 324 Total

o Ground at 109 Installed +2 at 107

· Vac Pump –pulls 14 inches

· Belt Drive

· AFR 227 #1121 Heads-Comp Ported

o T&D 1.5 Shaft rockers

o Trend .187 wall tapered pushrods

o PAC Springs

o Titanium retainers

· Edelbrock Super Victor 2 2982 Manifold

o Port matched only

o 4500-4150 reducer

o 4500 Dedenbear TS-6 disc stop

o Carb listed above

· 1-7/8 Header-3-1/2 Collecter

· 1.82 Glide protree brake

· Coan convertor

· 5.14 9 Inch

· 14x32 Goodyears

· 2960 lbs-tube frame 4 link

I normally run at Bandimere Speedway where no air is king (usually 8000-9000DA and 10000 is not unheard of). The 3 circuit deal would run good but the plugs are unreadable with soot and would hardly heat (maybe 200) even with low jetting in the 80s and no PV. I have not run it all out but the head and manifold change picked up almost 4 MPH from my old 1988 bowties and Prof products manifold- so now can go 11.50 ( S/ST index here) at 124 and change. Now that I have the 2 circuit deal on there I can tell it is already building heat when I get it to idle which tells me you guys are onto something and I think this thing will cure a lot of my consistency issues when I get it tuned correctly. It’s so fat with 3 circuits that Vapor Pressure swings will make it really difficult to set the stop as it will pick up 4-5 tenths. Hope this is enough info to help—if not let me know what you need-appreciate all your insight. Don't know how to post pics here or would.

Sun Jul 31, 2016 9:23 pm
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Joined: Fri Feb 08, 2013 5:50 pm
Posts: 2367
Plug the middle e-hole, leave the other two open. As far as idle, each Dominator body has a mind of its own, and can want something different, Make sure the factory installed upper idle feed restrictions are removed in those metering blocks. Timing locked to full advance? If it is try going to .041 for the idle jet, .065 for the idle air bleed. If you close the throttle blades fully does it just cover the t-slots?

Mon Aug 01, 2016 9:58 am

Joined: Sun Jul 31, 2016 9:03 pm
Posts: 2
Hi Mark sorry so long to get back. Work and lack of brass setscrews set me back. I did as you suggested and what a difference-this thing has throttle response like it's at sea level and hits the convertor super clean. I did have the correct e-hole plugs blocked before- and now it idles at 1100 with maybe a little less than the .020 transition slot showing and screws out 1 full turn and doesn't stumble at all. I won't be able to run this for a week but have a couple questions-as I now have 100 brass set screws how far on each side of the current setting should I make? Thinking about 5 steps each way in case I need to make some minor tuning. Also the old carb I have has the soft progressive linkage and the one i built has the linkage that opens primaries about 30 degrees before secondaries tip in. Thinking from drivability standpoint the linkage I have will keep the plugs cleaner as it's only on the primary side driving through pits and lanes. Is there any benefit to different linkages? Thanks again for you and others insight- very pleased with results and sure it will pay dividends on the track.

Fri Aug 12, 2016 6:36 pm

Joined: Thu Mar 28, 2013 6:09 am
Posts: 729
Mark would he benefit for a set of .600id 20 hole boosters??

Sat Aug 13, 2016 8:59 am
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Joined: Fri Feb 08, 2013 5:50 pm
Posts: 2367
As far as idle jet I wouldn't change it, sounds like it's close, you can try going up .003 on the idle air bleed if you want to lean it a little more. As far as boosters, it won't see as much from 12 to 20 as it would from stock, and his heads are pretty good, so I wouldn't think it would be worth the change. Using better booster inserts is about improving atomization and distribution, engines with quality atomization and distribution in the induction will be affected less if at all than one that has a less than ideal induction.

Sun Aug 14, 2016 3:08 am
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