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Holley 350 carb (7448) problems
https://slantsix.org/forum/viewtopic.php?t=37563
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Author:  mopardemon71 [ Wed Oct 28, 2009 8:11 am ]
Post subject: 

Lou a friend that eats ,sleeps and s#@ts holley said to have the metering plate mounting surface machined or checked. He loves holleys but that is what each carb he has ever got (40 years) checked and machined. He told me that it will run but horribly and a 6.5 PV should be all you need after that. I'll send you more info if you want just let me know if this is interesting to you.

Author:  Dart270 [ Wed Oct 28, 2009 6:48 pm ]
Post subject: 

I'm interested. Which face needs machining? I assume you just mean putting it in a mill and facing one side??

Lou

Author:  mopardemon71 [ Wed Oct 28, 2009 10:23 pm ]
Post subject: 

It's where the metering plate bolts to the body by 4 screws. The factory over torques those screws and it tweaks it. It will show no leaks on the out sde of the float bowl but the leak is inside. I will work on some pic's to clearify for you. :D

Author:  mopardemon71 [ Wed Oct 28, 2009 10:25 pm ]
Post subject: 

Sorry, the body surface to metering block area.

Author:  Dart270 [ Thu Oct 29, 2009 9:33 am ]
Post subject: 

So, you mill that metering block surface flat again, but not the carb body itself?

Hard to believe you can tweak the metering block with those screws. I always crank the crap out of mine, but with only a nutdriver. I've never had a problem there.

Lou

Author:  Wizard [ Thu Oct 29, 2009 10:00 am ]
Post subject: 

All too often. I have few old carburetors warped because of over torqued screws. Torque just enough to seal. That all is needed.

Cheers, Wizard

Author:  Dart270 [ Thu Oct 29, 2009 2:09 pm ]
Post subject: 

OK, when I said "cranking the crap" I meant with my careful hands. 8) Not enough to warp. Plus this carb would not run out of the box.

I may try the milling. Personally, I don't like the classic Holley 2bbl/4bbl design, but my 500 2bbl has been really good.

Lou

Author:  mopardemon71 [ Fri Oct 30, 2009 7:57 pm ]
Post subject: 

No this all happens when Holley puts it togather :x . The body of the carb needs it, where the meter block seals against it.

Author:  radarsonwheels [ Sat Oct 31, 2009 11:16 am ]
Post subject:  Warpage

Should be easy enough to check with a straightedge? Do the edges of the holes pull up into ant-hills?[/list]

Author:  Dart270 [ Sun Nov 01, 2009 6:40 am ]
Post subject: 

OK, carb body. Will check it.

Lou

Author:  radarsonwheels [ Sun Nov 15, 2009 11:01 am ]
Post subject:  350 tuning effort

Sorry I got all hot about working on my holley then my swinger started leaking oil bad and then my d-150 started running horribly. I work a lot so my days off were consumed with these not fun problems.

Today I finally investigated my metering block. I had forgotten that when I swapped my worked head (w/ headers and 2 barrel) onto a replacement block last year I slightly detuned the carb to work with a stock solid cam. The hurt block I took out had a mystery cam.
The setup for the cammed block was 66 jets blocked PV

Turns out I had 64 jets in her with a 6.5 pv when I was posting before. Now it makes sense that it was pig rich at WOT and ran best at 2/3-3/4 throttle. It cruised at around 30" of vac. with an af in the low 12:1 range.

I put some 62 jets in her and clipped some wire off a piece of spring I had laying around (the straight part at the end) No micrometer at home but the wire seemed to be more than 1/2 as thick as the pcvr's. I put the 6.5 pv back in and went for a ride.

The throttle is much snappier and only makes it to low 14:1 area a/f before the PV opens and drops to the low 12:1 range. I'm gonna try some 60 jets with a higher pv next. For some reason I have lots of 6.5 pv's but no higher#. Also have some 58 jets but no 60s...

Anyway, I hope it's not too late to help you with your dilemma and now I'm zeroing in pretty good. I'll mic up that wire when I get a chance.

Kevin

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