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76 Vette with Holley 700DP... leaks

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  #1  
Old 06-19-2007, 07:53 PM
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Default 76 Vette with Holley 700DP... leaks

Hi guys.

I just bought a 76 corvette. It has an Weiland Team G intake manifold and a Holley 700 DP carb (0-4778-4). I drove the car for a few days and it was fine, then one day when I started it the front bowl started to leak from the gaskets. I replaced the gaskets and it seemed to be working fine... drove it for half an hour with all kinds of traffic (from stop and go to 70ish... my speedometer doesn't work). The next day when I started it again, it was leaking again (even worse, I think) from the same spot. Today I bought some spray on gasket sealer, and figured I can try that next.

What do you guys think the problem is? What do you suggest I do next? If I can't fix the current carb, what would you suggest I do? I could get a new Holley, or buy a Q-Jet, but then I'd have to get another manifold as well...

Thanks!





 
  #2  
Old 06-19-2007, 08:23 PM
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Default RE: 76 Vette with Holley 700DP... leaks

Possibly the fuel bowls have been tightened so many times they may be deformed, take them back off and lay them on a known flat surface and check for gaps on the gasket surface.
 
  #3  
Old 06-19-2007, 09:23 PM
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Default RE: 76 Vette with Holley 700DP... leaks

When ya tighten down the bowl screws, ya don't have to strain at it, good and snug is about right. If ya put too much pressure on the gasket, you can cut into them and possibly cause another leak. You shouldn't need a sealer. Just make sure everything is aligned, and snug it up.
 
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Old 06-19-2007, 09:44 PM
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Default RE: 76 Vette with Holley 700DP... leaks

Hi Yellow76, Get that carb fixed now or stop using it untill you do. I remember how happy I was when I got my Vette, I couldn't wait to drive it all around town, but your playing with fire! Don't take a chance and have it burn up on you.
PG
 
  #5  
Old 06-20-2007, 08:04 AM
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Default RE: 76 Vette with Holley 700DP... leaks

I had a similar problem with a Holley DP.
Replace the bowl gaskets with the blue ones from holly. (only the blue ones)
All the other brands suck!
When you put them in don't over tighten.
This should solve your problem.
Good luck!
 
  #6  
Old 06-20-2007, 03:52 PM
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Default RE: 76 Vette with Holley 700DP... leaks

Guys,

I did replace the gaskets with the blue holleys. I'll have to just try to line them up again, but if that doesn't work should I try the gasket sealer? If I take the bowl off and it looks a little deformed, is there anything I can do to salvage this, or should I go right out and buy a new one. If so... should I try to find myself an old q-jet and manifold, or just buy a holley 600?

And no, of course I'm not driving it around with gas spitting out of my carb!

Thanks for your advice.
 
  #7  
Old 06-21-2007, 03:07 PM
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Default RE: 76 Vette with Holley 700DP... leaks

If you have access to a really, really flat surface like a cast iron table saw, you can sand the mounting surface with wet/dry SiC paper. Start with something in the 240/320 range and finish with 600/800 range.

IMO, a DP is probably overkill unless you are running a highly modified engine. A Q-jet when set up properly, is a good street carb.
 
  #8  
Old 06-21-2007, 03:17 PM
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Default RE: 76 Vette with Holley 700DP... leaks

I pulled the bowl off last night and it didn't look deformed at all... but I didn't really have access to a really flat surface, so I'm not completely sure. Tonight I should have a bit of time to mess with it, and I'll see how it's going after that.

Yeah, the carb is way overkill for the engine - it's just what was on there when I bought the car (a week and a half ago). The engine isn't modded that I know of, except I was told that the guy before the guy I bought it from put a cam in it... I have no idea what cam... just that he put one in. I was just trying to make this carb work for a while and then sometime down the road I'd replace it either with a rebuilt Q-jet or a new, smaller, Holley.
 
  #9  
Old 06-21-2007, 08:31 PM
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Default RE: 76 Vette with Holley 700DP... leaks

From what I read on another forum, stay away from the Holley spreadbore. It has none of the good features of a 4150 style, e.g., externally adjustable float level and none of the good features of a Q-jet. Q-jets get a lot of undeserved bad press but IMO are a pretty darn good, all around street carb. Good luck with however you go.
 
  #10  
Old 06-23-2007, 06:50 PM
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Default RE: 76 Vette with Holley 700DP... leaks

are you sure the leak is from the bowl gasket? the bolts that secure the bowl have washers that deteriorate and leak , teflon washers are sold to fix this problem, also the accelorator pumps are bad to leak, also a easy replacement. chris
 


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