Holley 6709 double pumper 750 carb info

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Bewy said:
RB,
Engines were backfiring in the 1950s when Holleys were designed & sold.....Didn't just start happening many years later....when H brought out a fix. It was an engineering failure, & a very simple one, that the carbs did not have BF protection from day one.
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Bewy, a backfire won’t blow a power valve. And even if it did, why not fix the ******* backfire? You make it sound like everything backfires. I haven’t had a blown power valve in YEARS.

And I’ll say it again, it’s almost NEVER a power valve that is leaking. Yet it gets the blame because blokes like you keep spreading bullshit a mile wide and ten miles deep.

If you need blow out “protection” you need to learn to tune **** up. Or better yet, get some clubs and go play golf.
 
Which begs the question.....
If a backfire doesn't blow the PV......why did Holley add back fire protection.
 
Bewy said:
Which begs the question.....
If a backfire doesn't blow the PV......why did Holley add back fire protection.
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Because the market wanted it. That’s why. Morons on the internet sniveling and whining like school girls about something that wasn’t.

Which begs the question…
Why do you care? You think the Carterbrock is the ultimate carb. So why **** up this thread with your continual bullshit?

Take your nonsense somewhere else. This kid wants to learn. He doesn’t need fools like you sending him down a rabbit hole looking for performance from a carb that can never compete with a Holley design I either power or driveablity.
 
RB,
The only fool on this site is you & you are the one promoting bullshit. Chopping & changing the story line when you get caught out. So you haven't had a blown PV in years. Does that mean you did have a blown PV at some point in time?? The market only wants something.....if there is a demand for it.
Anybody who has been in this hobby long enough has had an unfortunate backfire. Could be as simple as the auto choke failing to activate. Not the fault of the operator & nothing to do with tuning. Often, just bad luck.
You talk about Holley power & reliability, then in post #23 say another reason NOT to buy Holley....
 
Bewy said:
RB,
The only fool on this site is you & you are the one promoting bullshit. Chopping & changing the story line when you get caught out. So you haven't had a blown PV in years. Does that mean you did have a blown PV at some point in time?? The market only wants something.....if there is a demand for it.
Anybody who has been in this hobby long enough has had an unfortunate backfire. Could be as simple as the auto choke failing to activate. Not the fault of the operator & nothing to do with tuning. Often, just bad luck.
You talk about Holley power & reliability, then in post #23 say another reason NOT to buy Holley....
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Pay attention. I never tell anyone to buy Holley. EVER. So get that right.

I tell people to buy clones. Or better yet, step up and buy something like the BLP BX4 and have something worth having.

And yes, I haven’t had a blown power valve in years. In fact, it’s been so long I’m no longer sure it was a blown power valve at all. I can’t say at this point if it was or wasn’t.

What I can tell you is I have had engines backfire (mostly operator induced things) and not one time has the power valve been blow out. Just happened o the dyno the other day. Some dumb *** forgot to turn the fuel on to the pump and it went lean and back fired (more than once) and the power valve is just fine.

And guess what? I know for a FACT there isn’t power valve protection in that carb. How so? I put it together. And I do not use that garbage.

So there is a recent, real world example of your bullshit. So stop talking about what you don’t know.

Stick to Carterbrocks and their low power output.
 
I think it's great a young gun is into our old stuff! Rebuild your carbs, have fun, if they don't work out you can sell them already rebuilt.
Yes,you've been advised even if it's what you don't want to hear it but sometimes you just have to learn the harder way. Good luck !
 
Those aren’t going to be good carbs for what your doing. I’d sell them and look for a set of 6109’s (750 DP TR carbs). Good carbs for your application. Being that you’re learning these would be a lot closer with the “out of box” calibration. A set of 3310’s (750 vacuum carbs) would also work and are cheep and readily available. They would need some additional calibrating to really get them dialed. I’m suggesting stuff that’s a bit more budget friendly. Obviously a modern set of purpose built carbs is going to be easiest. Those come at a cost though.
 
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Rat Bastid,
If anybody needs top pay attention & learn to read it is you.
I never said the carb in question had PV protection. I said the lack of PV protection was one of the failings of Holley carbs. If the clones do not have blowout protection, then they are no better. Just because you haven't had a PV failure from a backfire doesn't mean it doesn't happen....
 
Well quick up date! I will have my block going to the machine shop soon! It was going to be sooner but everything seems to be stopping me from completing my 2 year goal! but life goes on! So I also have more bits and piece to clean up and obsess about! I got my 68 big block dart bellhousing mocked up for fun and I just got my tti z bar for my shorties!

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Well good news I'm that much closer to testing these carbs! Soon find out if they run rich enough not to lean everything out. And worse case scenario I'll get ahold of some modern double pumper and spend the money lol
 
Well happy spring everyone! Latest update! Engine just came back from the machine shop! I also got the rotating assembly ballenced. So she got some paint! Pretty exciting!

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Got my roller cam in today! not sure if it's right.. but I'm sure I'll be fine!

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Also got this fancy accell dualpoint! NOS goodness! But I'm thinking about pulling a point and running a 6AL along with it.. but I'm just a spazz that likes the look and simplicity of cool old stuff so probably not.. but dwell adjustment and ball berings! Thats super slick!

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Couple of comments:
- dual point dists were invented to increase dwell time so that higher rpms could be achieved before misfire. This only applies to inductive igns, points Chry elec etc. The 6AL is a capacitor discharge [ CD ] ign & works on a different principle. Dwell time is not a factor. So using a twin point dist just introduces more parts that can fail....& provides no benefits with CD.
- any points dist starts retarding the ign timing once it spins because the rubbing block wears. It is a dinosaur!
- use a Chry elec dist to trigger the 6AL. It has no parts that wear to change the timing & it triggers more accurately than points. It is a no brainer.
 
I gotcha buddy! Thanks! I do appreciate the input! I did mention though I would pull a point, but only if it was connected the 6al.
It's a dinosaur but my points on the /6 usually last 2000 miles.
I drive less than 500 a year. Alaska gets basically 3 months of summer 9 months of crap rain/snow. So points last for ever if you only get 90ish days of summer lol just gata check be for and after any dragstrip fun and it'll be fine. But I'll probably get a fancy one down the road. Who knows I am just a kid, and there's a long journey ahead for the demon and I lol but thanks.. I hope I have brains haha I do feel dumb all the time.. and I am a millennial.. so who knows.. will just half to see hahah
 
Making headway on the demon!! Cool update on the carb! I used the 6709 carbs on other rides! Well really the good one went on the stock 76 318 with a dualplane edelbrock! Headers soon! cause I allready had them... but 800 bucks 135k miles 727 and rear some sort of rear gears lower then 3 something(only slightly less gutless with new intake/carb) but gets 18 mpg highway with those mudders! Fortunately the dude I bought it from, swaped everything brake related, the front window front/rear suspension, pretty much everything.. but the engine.. and I'm pretty sure? a super loose intake = terrible engine behavior.. so I wanted to be nice but that's a dream ride right there! Well shes lookin rough.. but drives great!! so I pounced on the deal!

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2x4-451Demon71 said:
Making headway on the demon!! Cool update on the carb! I used the 6709 carbs on other rides! Well really the good one went on the stock 76 318 with a dualplane edelbrock! Headers soon! cause I allready had them... but 800 bucks 135k miles 727 and rear some sort of rear gears lower then 3 something(only slightly less gutless with new intake/carb) but gets 18 mpg highway with those mudders! Fortunately the dude I bought it from, swaped everything brake related, the front window front/rear suspension, pretty much everything.. but the engine.. and I'm pretty sure? a super loose intake = terrible engine behavior.. so I wanted to be nice but that's a dream ride right there! Well shes lookin rough.. but drives great!! so I pounced on the deal!

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O ya! the Guage reads like 11.5 to 1 something and 14 ish when decelerating! So carb works great! I basically left it in stock rebuild specs and tuned with a vacuum Guage. Super bad gas mileage for any heavy footer though! Stay out of the secondaries and she's not to thirsty!
 
So the demon's got 2 hoods I would like to fit everything under the dual snorkel hood.. an almost impossibly.. But we can dream can't we!
So worse case scenario I can cut it and stick the just for looks scoop out the top lol But yes I will leave my original hood untouched
I just can't believe, that I possibly have one of the LAST bought in alaska 71 dodge demons! At least 1 of 5 that are up here, and 3 of them are 72's !!
so for a poor kid like me it's a dream!!
I'll try and post plenty of picks of my 20ft paint job roadkill car during the build cause it's almost ready to drive!!! Not quite race yet.. but drive for sure!!

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