I have several Holly 500 two barrels from circle track days. I Have heard they are not the Ideal slant six carb but i would like to try one. My car is a 3000 pounds 3.55 gears 9to 1 comp.clifford short headers stock torque convertor. Does anyone have a baseline setup,jet, squirter size,powervalve #, acc. pump cam color, 50 cc 0r 30cc pump. Any info would help. Thank You.

Is this the Keith Dorton series carb? Or just a run of the mill OTB 500.


I have been working with one fo these on a basically stock engine. The problems I have been having is holding a flat A/F curve at WOT and the lean spot between the cruize and when the mains come in. They will work good, but I am wanting to lean down my cruize for dialy driving.


OTB 500 you can probably run the blue pump cam with the 50cc pump (they need the big pump). The blue pump cam is agressive but shuts off after so far ( with the two barrel this will work). The squirter size depends alot on how the rest of the carb is set up, a .031 is what I am running now, but if you go the carb setup rich you can get by with a smaller squirter. Jets in the 74 to 78 range and I am even running 80 at the moment. Power valve around a 4.5 could work, but again a lot depends on what your doing and how the rest of the carb is set.

Standard OTB 500 will do good with this, but if you have a big cam you might want to go to 3.5 or even a 2.5 PV, and it may want more MJ depending on engine. My setup hold Zero vacuum in the intake at WOT with this carb. If you have enough engine for it to hold vacuum in the intake at WOT I would think you might want less Main Jet (MJ). But with such little air pulling form engine ( it being stock) I find it wants a lot of jet.


MJ - 76
PV - 4.5
Blue cam
squirters - .031
Float level - High ( midway at sight plug)


This should run good, but be a bit rich for cruize, but still no bogs and good WOT A/F.


Ofcourse there is so much that can change with Altitude,engine setup and other things but this should get you to a smooth running piont that you can start tuning from.


Jess

I have used one of these with great success on many different combos. I think my best setup with a medium buildup is around 70 main jets, 50cc pump, 6.5 PV and stock squirters. I think this is pretty close to how it came outta the box, actually. I jetted up at first, but once I got an O2 sensor and did some track testing, I came back down in jetting. Great mileage and very simple carb. Best times 14.90s with 3.00 gears, medium built motor, light car (about 2750 with me and 12 gals).

Have run these on almost stock motor, and will probably try it on my more built one that is going into Project V this Spring - around 270 HP.

Lou

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Home of Slant6-powered fun machines since 1988

Lou,

How good is great mileage?

I have been toying with the idea of running one these or the 350 version instead of the BBD.

Which would give the best mileage? or does it matter...

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Mileage was around 22-23 MPG hwy on my 68 Dart running 17s at last use. The MP-EFI took it up to 24-25 MPG. I also drive pretty fast - 70-80 usually. Use on Project V since then, which is not street legal...

My guess is 350 might be slightly better afor MPG nd can make good HP. Seymour went in the low 14s in his white '62 Val with the 350, and 13s with the 500 IIRC.

Lou

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Home of Slant6-powered fun machines since 1988

What jets do you run in the 350?

There are quite a few threads on running these carbs, here on the forum. I have read quite a few of them. I have the holley 350 on my slant. I am still playing around with it. Right now I have the 57 jets in it with a 8.5 pv. I need to get a vacuum gauge to help see what is going on.

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Excuse me, does this smell like chloroform to you?

I've never used a 350.

Lou

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Home of Slant6-powered fun machines since 1988