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| need help selecting a new carburetor https://slantsix.org/forum/viewtopic.php?t=66525 |
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| Author: | wjajr [ Thu Mar 31, 2022 1:45 pm ] |
| Post subject: | need help selecting a new carburetor |
1967 Dart rag top 225 ci Oregon Cam Grinding #346 compression 9.6:1 Clifford shorty intake, & headers, duel exhaust pipes all the way to rear bumper ported head, oversize engbuilder valves 2600 rpm stall converter & 904 with shift kit will turn 5500 - 6000 rpm easily 8 3/4 Suregrip 3.55:1 gear 24" tires Car runs 3000 rpm @ 60 mph, its a cruiser, I don't race, but like to get onto her once in while. Current carburetor is a worn-out Holley 390 cfm [0-8007] that I can't deal with any longer its has given its all. What can I replace it with other than the same make and model 0-8007 because the darn things are over $650 now. Holley 600 cfm with electric choke and vacuum secondaries are reasonably priced but may be too big Edlelbrock has the 500 cfm in the Performer and AVS2 series. Summit has 500 cfm in their Racing Max performance line. It looks like a Holley knock off Any of the above carburetors you guys favor? Or, something not listed above? I've also considered fuel injection, but that is a lot more dough with fuel tank upgrades, and all the plumbing, but most likely would provide better fuel economy, and drive-ability. |
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| Author: | Rick Covalt [ Thu Mar 31, 2022 2:27 pm ] |
| Post subject: | Re: need help selecting a new carburetor |
The Edlebrock 500 would be a good choice in my opinion. Lots of tunability from the top of the carb. I have run them on everything from my truck to my race car. |
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| Author: | wjajr [ Fri Apr 01, 2022 5:32 am ] |
| Post subject: | Re: need help selecting a new carburetor |
Not having to pull off fuel bowels to tune is a big huge plus. Will I need to install a fuel pressure regulator with an Edlebrock 500, or is the factory mechanical pump's pressure low enough to work? |
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| Author: | and739 [ Fri Apr 01, 2022 6:53 am ] |
| Post subject: | Re: need help selecting a new carburetor |
Quote: Will I need to install a fuel pressure regulator with an Edlebrock 500, or is the factory mechanical pump's pressure low enough to work?
I was curious about this too so I went and found an Edelbrock AVS2 Series Carb Tuning Guide online. According to this, fuel pressure should be 4-5 psi minimum. Then I found an instruction for the Performer Series. This one mentions at idle psi shouldn't be more than 6 but should not crop below 2. Aren't factory mechanical pumps are 3-4 psi, or something like that?
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| Author: | Dart270 [ Fri Apr 01, 2022 7:48 am ] |
| Post subject: | Re: need help selecting a new carburetor |
Factory pump pressure and flow are perfectly adequate for this and almost any other carb. You do not need gauges or regulators. I have found quite good results with both Performer (AFB) and AVS type Edelbrock 500s. They are pretty close to bolt on and go, and often I have messed around with jetting/rods and ended up almost back to stock jets/rods. I always get the tuning kit ($50?) for that carb. All that said, I put a Street Demon 625 "goggle valve" AVS/Thermoquad-esque carb on my Project V (more built motor) a few years ago and it works REALLY well, probably better than all the Edelbrocks. If I were to buy another carb new, I would probably get this one, even for a somewhat milder motor. This has small primaries, so response is really good. One stoopid thing is you cannot change jets from the top like an Eddy so you have to pull the carb off and invert it to do jets. Primary rods and secondary adjustment you can do from the top easily. I like the Holley 500 2bbl also for simplicity, but it is harder to get the mixture right over a wide range of street driving conditions. It enables a big pump shot, which the Slant generally really needs. I have never gotten a Holley 4bbl to give sensible street driving conditions on a Slant, although I admit I have never started with a new or known good 390 carb. Probably that is the best one. Disclaimer: NO carburetors are going to give "new car" like performance and/or driveability except on the day you tuned them, assuming you do a very good job tuning within their limits. A well designed EFI system is much more complex, but gives better results in nearly all cases for street driving and usually racing. I hope to convert the last of my Slant cars to EFI in the next year or two. Project V is almost fired up with MS3X... Lou |
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| Author: | wjajr [ Fri Apr 01, 2022 1:13 pm ] |
| Post subject: | Re: need help selecting a new carburetor |
Lou, Thanks for the Street Demon 625 tip. Never really looked at them because they are over 500 cfm, and thought they would be too big. I have been reading up on the Street Demon 625. Seems most folks like it. Looks like the 625 requires a special air cleaner that is 3"x14". Is that big thing going to fit under my 67 Dart's hood? Currently I have a 2"x10" Edelbrock chrome cheepy on top of the worn out 390 Holley and it is a tight fit. Will a HLY-20-7 Holley Chrysler throttle adapter work? What did you use for throttle cable-kick down & return spring bracket? Currently I have a BPE trans & throttle cable bracket, plus a crappy return spring bracket that ain't cutting it. I would like to get a bracket that will receive both Mopar cables and return spring. Bill |
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| Author: | Dart270 [ Sat Apr 02, 2022 4:48 am ] |
| Post subject: | Re: need help selecting a new carburetor |
I use a drop base 3X14" cleaner on most carbs. You can get the top of the cleaner 1 - 2" above the face of the air horn depending on how much drop the cleaner has. That is, the stud that comes out of the carb will be 1-2" protruding from where it enters the carb, plus the little for the nut to go on. Takes up less space vertically usually than those 2X10" cleaners. I assume you do not have many spacers between manifold and carb? If not, you will be OK. I always make my own brackets for carbs and kickdown cables/linkages/springs, so others can maybe help you with that. I use Lokar throttle cables and similar or other universal ones for kickdown. Lou |
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| Author: | wjajr [ Sun Apr 10, 2022 9:27 am ] |
| Post subject: | Re: need help selecting a new carburetor |
Does the Street Demon 1901 have the same foot print as a (4160) 390 Holly carburetor? Will the HLY 20-7 Mopar throttle bracket work on the 1901? I still can't locate a return spring and throttle/kick-down bracket that plays nice with stock Mopar cables. The current one I have is this one, problem is it tends to bend, and then won't fully close the throttle back to idle. |
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