How should I seal throttle linkage in home-made carb box?

I am considering a home made aluminum carb box for a cheap blow thru system. I see the $700 ones in summitracing but I would like to weld up my own for about $10 in materials. The only thing I havent figured out is how to seal the throttle linkage so I dont loose boost. Any ideas??
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Good question. I would think that you would find it easier to enclose and seal a cable rather than use the stock mechanical linkage.
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appropriately sized O-ring, made of nylon, brass or neophrene would seem like a good starting point.

the boxes are the worst method, fabricate a bonnet and eliminate all those other hassles
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I just had a thought. Would a front oil seal from a SBF timing cover be sufficient?
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I ran a box without a seal. Just close tolorence. Put the boost gage in the intake. Don't worry about what little boost you lose in the box, since your measuring at the intake.
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why running a box, how about a carb hat only?

The only reason I am considering a complete carb box is because I was warned of potential problems with old Holley's leaking around the throttle shafts under boost with a bonnet.

You could weld a bung into the side of the box, and run a rocker shaft through it with an O-ring. just make it a 1:1 arm ratio.

I've seen dyno comparisons of the enclosure setups vs. the bonnet/hat setups, and from what I remember the enclosures perform a lot worse... probably because they don't really direct the air into the carb inlet like the bonnets do. Even if you were getting some boost linkage through the throttle shaft bushings... I think those are a LOT tighter clearance than you'll ever get on a throttle cable passing through, and regardless you're talking about pushing over 600CFM through the carb, how many CFM do you think can leak through the tiny gap on the throttle... maybe 2?

But if you're set on the carb enclosure design, I'd just use an appropriately sized rubber o-ring, and maybe some silicone to seal it up even better if you think necessary.
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