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I have a big block and I just got a th400 built and have a 2600-2800 stall, gear 3:90 and a single plane intake. Its a street/strip car but the car see more of the street than the track:confused:
 

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I recently did the governor mod on my th 350. Im all smiles now. Regular part throttle shifts with full throttle 5500 rpm shifts. It actually gets in to an rpm range the cam likes. :D
 

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I was lucky, got it first try. Used stock springs and IIRC I went 4 grams total lighter on the weights. The original weights that were on the governor were a lot lighter than i expected.
 

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I have to drill a hole on the single plane intake. That means I have to remove it?
Really? There are NO provisions on that intake?
There is usually one on the rear face of the manifold, below the carb mounting flange. If not, that's where I would CAREFULLY drill and tap a 1/8" NPT hole for a small vacuum hose-barb.

You may be able to do this by simply removing the carb and taping off the intake runners to prevent any material getting away on you. Drill and tap the hole, and then vacuum up the debris.

Use extreme care when tightening any pipe thread fittings on an aluminum intake, as the the thread is tapered and can crack the intake if over-tightened.
 

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I have to drill a hole on the single plane intake. That means I have to remove it?
Not necessarily. "Manifold" vacuum only means a full-time vacuum source that is there even at idle. "Ported" vacuum is NOT there at idle, and that's the main difference between the two (there are subtle differences besides that, but they do not apply here).

So you can use a carb port that has manifold vacuum just as easily as using a vacuum port that's in the intake manifold itself, if you follow me.

If you have a Holley, the metering block has a ported vacuum port- do not use that. You can use a port that's located on the baseplate, but still double check to see that it has full vacuum at idle.

An Edelbrock carb has a manifold vacuum port on the front, driver side.
 

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WFO
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"Same thing" = shifting too quick?

What is the rear gear ratio? If you're talking about part throttle, low throttle shifts, they do tend to be very quick if there's no load on the engine. The best way around this is to shift it manually. It will always shift through the gears quick if left in Drive, under low load, light throttle settings.
 

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Yeah, w/those 3.90 gears it's gonna shift through the gears quick under light throttle/light load conditions. It's normal for it to do that. Holding the gears manually is about the only way around it.
 
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