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AIR POWER
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153 Posts
Discussion Starter · #1 ·
I have an old ass 800 dp holley and have tried rebuilding it and still have something wrong with it. Can anyone send me in the right direction on where is the best, and cheapest place to buy a new 850 dp. Also I can not find anywhere in my area where you can still take a carb to be flow tested and rebuilt, is there still places like this anywhere, maybe where a guy could ship his carb to get fixed? Thanks.
 

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Sit N' Spin
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1,345 Posts
I have no experience with Bigs Performance, but a lot of people I have talked to seem to favor them for carb rebuild and setup. Here's their website.

http://www.bigsperformance.com/

I believe Shaun (actual screen name) here on the boards recently had a carb built by them. Reading his post about it, for shits and giggles on the dyno they tried changing the tune on it and ended up losing power as a result.
 

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Sit N' Spin
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1,345 Posts
now, that there is funny.

no affence, but arnt those your carb threads.
I meant no experience with Bigs Performance. Just corrected my wording. Thanks.
 

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383 Posts
compressed air

take your rebuilt carb(that doesnt run well) and take it back apart, blow compressed air through every square inch of the thing (exept power valve) , all and every hole in and on the thing. blow in vacume holes, find out where it is coming out, and blow it back the other way. holleys are simple carbs.

also you need to carb dip it ( clean ).

i understand that your probably frustrated with the thing, and just want a pro to finish what you started. i dont blame ya. i had my 650 dp pro done. cost me $300.00 . then i needed a bigger one. found an 800 dp on craigslist for 100.00 . there was no way i was spending another 300.00 on top of that. my neighbor told me (holleys are the simplest carbs on the planet).

i took his advise. the thing works perfect.

compressed air!!!!!!!!!!!!!
 

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113 Posts
First off what is wrong with it???
My race buddy taught me all sorts of things on holley carbs and mine
ran perfect after we rebuilt it.
And X2 on the compressed air that sleekcraft mentioned. Take off the metering blocks and blow ever hole and passage with air to make sure there is no debris anywhere in them.
 

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AIR POWER
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153 Posts
Discussion Starter · #11 ·
When I get into the four barrells it surges in and out like it is running out of fuel and wont let me stay wide open, also when I accelerate I can hear a whistle out the scoop. I pulled some plugs to check after I ran with it surging and they were really light tan. I then put some large ass jets in the secondaries to see if that would help and the plugs stayed the same color. I know it has fuel because I just installed a new fuel pump, regulator and a guage and it has 7.5 lbs constant pressure, it did only have 3.5-4 psi with the carter fuel pump. The distributor is a new HEI and the timing is set correct I even tried to retard and advance it out of the setting to fix it.This carb is very old, it came on the boat in 1973, its been dipped cleaned rebuilt. I did notice that the throttle shaft has some up and down play in it and seeps a little gas very little but you can see it. I am looking on ebay for a new one.
 

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Administrator
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11,501 Posts
Sounds like a vacuum leak somewhere. Check all your base gasket setup and if the throttle shaft is "excessively" loose this could be some or all of what's going on (vacuum leak). Vacuum leak can also be on an intake port(s) if the intake has gotten loose. It will kill any attempt to get proper fuel mixture and will surge if lean enough, as well as hurt parts if run wide open in this condition.

The 800 (old 4780) is also an excellent carb and will run better than the 850 on many stock setups. You should be able to get bushings for the base plate or a new base plate pretty easily.

Just a stab in the dark.
 
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