750 on a 318

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daredevil

daredevil

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Before you chastise me hear me out. Right now i,m tapped out. Wife had hernia surgery and crappy insurance left me a hefty bill to pay so no car bucks. I have a 750 proform mechanical secondary carb thats almost new. I want to try and use it to get by for now. I stuck .067 jets in front and a pair of .076s in the rear. This should lean it out quite a bit. Does anyone know if plugging a couple air bleeds front and rear will correct it enough I can run it with no problems 318 is basically stock with a set of headers. Plan is to get a 600ish spreadbore when money allows. I have a plug in the back power valve and will adjust the secondarys off as much as possible. Any suggestions on front powervalve or different jetting? thanks DD
 
How about a TQ in the meantime? It will get better gas mileage ,and it will also give you more cfm,lol...
 
If you plug the air bleeds, you will be richening it up more. If you want to lean it with the air bleeds, drill them out larger......BUT if you do, do it in VERY small increments, since once metal's gone it's gone.
 
The correct power valve setting will require you to take a vacuum reading with the car at idle.
Google "holley adjustment" you will find the info, or go to your local library there are several good books on Holley carb tuning.
I think you can get the carb to work ok with some fine tuning.
 
StrokerScamp said:
If you plug the air bleeds, you will be richening it up more. If you want to lean it with the air bleeds, drill them out larger......BUT if you do, do it in VERY small increments, since once metal's gone it's gone.
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What i,m afraid of is jetting with a Pair of .067s in front that i may have to pull some air out to compensate or its gonna be too lean. Trying to balance it out some. Kinda big carb for small jets.
 
sireland67 said:
The correct power valve setting will require you to take a vacuum reading with the car at idle.
Google "holley adjustment" you will find the info, or go to your local library there are several good books on Holley carb tuning.
I think you can get the carb to work ok with some fine tuning.
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I have the holley book. Was just hoping someone had already tried this and had some working knowlege to pass along. You know,a good place to start.
 
Slap it on there and see what happens.
Deal with the details from there.
Hey if nothings else it's fun **** to try right?
 
I had great success with a 750 on a mild 318. The one I used had annular boosters so I'm not sure if the same tune would apply. I tryed all kind of jets and squirters and found it ran best basically the way it came out of the box.
 
It's already too big of a carb for a basically stock 318, but the mechanical secondaries will make it even worse. You might end up spending a bunch just trying to tune it because you'll likely need a variety of jets, squirters and pump cams to experiment with. If you don't have a choice, I'd somehow try to safely disable/disconnect the secondaries alltogether. Jetting a big carb leaner may create a very big lean bog when you hit the gas!
 
Do want to sound like an A**, but, judging from your pic, you've got a bunch more important work to do before worrying about a carb.
 
65Val said:
Do want to sound like an A**, but, judging from your pic, you've got a bunch more important work to do before worrying about a carb.
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Thank you for your fine observation and your judgement. Doing anything I can thats not going to cost. I,m trying to get the motor sealed up.When people start with dont want to, its because they do.
 
65Val said:
Do want to sound like an A**, but, judging from your pic, you've got a bunch more important work to do before worrying about a carb.
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Don't worry, you sounded just like an *** in a hole. Thanks for helping D/D with a minor issue while he's recovering from surgery and a lack of bucks. Your such a great help and a PILL to the fourm.:violent1:

D/D, Trailbeast has it right, just try it. I have found that combo a pain to deal with. Like Loco said, Unless you have a box of cams, squirters etc... it's going to suck.

Just get the primary dialed in as best ya can.
 
I have done it before.....like back in 99 !!

I used a 750 DP with mechanical choke on a pretty "wild" 318....by that I mean it had a .550" lift 280* 110 cam, double roller chain, edelbrock RPM Air Gap, milled 302 heads, that were ported/polished, heddman headers, open exhaust...no mufflers...MP electronic ignition...

Had to jet it 66-68 from 74/74 and adjust it all out but it finally ran pretty good....still rich all the time....never got to fully tune it out.

I have a 4777-2 now (650 DP) that is blowthrough modified, rebuilt and sitting on the shelf and I am gonna give the 4150 based carb another shot in the near future.

so bottom line to my reply is:

it will run....but tuning it may present some challenges.
 
i have no doubt it will start and run as long as the carb itself is sound. im not sure about drilling out the air bleeds, you may regret it down the road. maybe jetting the primary side to a 65 would help. i would make sure the floats are dead on and make sure every possible vacuum port is closed off minus the advance and the PCV and you have a great seal to the intake.. toss it on and see what it will do. i would start with the mixture screws 1 1/4 turns out and the idle jacked up some and the timing at TDC. it WILL run. get it to idle and set your timing and go from there. we recently tried an 850 DP on a bone stock 360 and it runs, but it is a little much for it. it cant hurt to try it out. my $0.02
 
So who has a 600 holley core on the shelf. Help thus guy out. Ill kick in some for a rebuild kit? Seems rob is a carb master maybe he can donate a rebuild service
 
daredevil said:
Before you chastise me hear me out. Right now i,m tapped out. Wife had hernia surgery and crappy insurance left me a hefty bill to pay so no car bucks.
DD
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I have a 2bbl Holley off a 360 if you want it
It was running and everything I just upgraded to 4bbl Eddy 1405 carb and the Pro Performance Air Gap intake
Here's the carb and manifold:

to see more pics go to my truck's site:

https://picasaweb.google.com/107180236275903734012/D100#



IMG00318-20110412-1743.jpg


PA120013.JPG


PA120014.JPG


PA120012.JPG
 
72ScampTramp said:
So who has a 600 holley core on the shelf. Help thus guy out. Ill kick in some for a rebuild kit? Seems rob is a carb master maybe he can donate a rebuild service
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I sure appreciate the fine gesture but hold the horses. There are those in much more need than me. This is just a bump in the road. I have a 750 Holley that fell off a shelf and bent the fuel level adjuster boss. I have a deal going for some chrome bowls and a friend who might buy it for 150. When it's back together. In the original post I was wondering if there was a recipe to tune the proform 750 to work for me someone knew. I have been broke before and will probably be broke again but I always get thru it. You guys are a great group. Thanks for the kind offers. That 2 bbl is mighty tempting. Had a 500 years ago on a 307 chevelle. Think up a fair price and pm me. Thanks a lot guys you made me feel special. This and what gdrill did for me gives me a feeling money can't buy. DD
 
daredevil said:
That 2 bbl is mighty tempting. Had a 500 years ago on a 307 chevelle. Think up a fair price and pm me. Thanks a lot guys you made me feel special. This and what grill did for me gives me a feeling money can't buy. DD
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here's a vid of the carb running around november:
[ame="http://youtu.be/93o2olRFZKg"]302 Found[/ame]

and i have no need for the manifold or carb.
i just hope you get your car on the road soon
 
I have a Holley 600 that I am not gonna use. It's a good core. If you spring for a kit and shipping I'll build it up and send it your way.
 
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