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Old 02-13-2007, 03:59 PM
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SBC 283 intake & Carb Swap Problems

I recently removed the stock intake and two barrel from my 1966 Chev 283 and replaced it with a torker 2 edelbrock intake and a rebuilt 600 cfm carb. The truck ran like a top before the swap, but now after I can barely drive it. When I start it up the idle takes forever to come down, and when I shift it into gear (its a 3 spd Automatic) it kicks extremely hard, (almost like I did a tranny drop) plus even at that point it will hold out and not shift until almost 5000 rpm. I hooked up the vacuum module just like it was before. I was told that the carb was rebuilt but I am not sure. MY question is how can a simple intake and carb swap lead to severe transmission problems and the idle never coming down? Please help as this is my race car hauler and the races are right around the corner! Thanks in advance!!
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Old 02-13-2007, 04:06 PM
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You kickdown cable sounds like it needs adjusted and or may have a vacuum leak. Check by spraying some carb cleaner around the base of the carb and see if the idle changes. You would be better off selling the torker and getting a dual plane like the performer. Your little 283 needs all the bottom end it can get. A single plane manifold is good for high rpm power.
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Old 02-13-2007, 05:14 PM
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Still need help?

Thanks for the suggestions. As far as my kick-down cable goes, its not even hooked up. And if there is a leak in the carb, can that cause the tranny to shift wrong? could it be something like the carb is not producing enough vacuum for the module on the side of the tranny? I unplugged the module and it did exactly the same thing.
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Old 02-13-2007, 05:43 PM
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"The truck ran like a top before the swap"

This would be reason enough to swap the 2-bbl back on it.

You more than likely have a serious vacuum leak. If you can't find it by spraying a combustible vapor around the intake and carb base, then it is probably sucking crankcase vapors into the intake ports from the interior side of the intake manifold.

When we change manifolds, we all assume that everything is machined to match up perfectly. Nothing could be further from the truth. If the intake and head surfaces are parallel in both planes, it is by the sheerest of coincidences. Please read this response to another member:

Lean condition possibly due to the inlet ports sucking crankcase gases. If the intake manifold/head surfaces are not perfectly square and parallel or if the intake gaskets are not properly fitted to cover the ports on the interior side of the manifold/head interface, this can happen. Ask me how I know.

You have covered everything else that could be causing this, so that is my best guess. I suspect that if you remove the intake, you'll see where the gasket has not been clamped on the interior side.

Measure the thickness of a new gasket. Get flat washers or shims that will measure that thickness. With the manifold off and the mating surface on the cylinder heads de-greased, put a dab of RTV on them and stick them on each corner bolt hole on the cylinder head. Let the RTV set up. Stuff paper towels into the ports to keep debris out. Make up 16 pea-sized balls of modeling clay. De-grease the intake manifold at the ports. Place the balls of clay on the top and bottom of each port, squishing them down well so they will stay in place. You want them to be thicker than the shims/washers that are RTV'd to the heads. With your fingers, coat a little oil on the heads where the clay will meet the head to keep it from sticking to the head. Now carefully place the manifold into place on the heads and use bolts on the four corners to just snug the manifold down until you feel resistance against the shims/washers. Remove the manifold carefully and mesure the thickness of the clay at all 16 positions with the depth function end of your 6" dial caliper. You'll know pretty quickly if the manifold/head interface is square. Record the measurements on the manifold with a permanent marker like a Sharpie. The widest measurement will be the standard to which you will want your machinist to cut the other positions on the manifold to make it square with the heads, thusly sealing the motor up.

I've explained this procedure to others who then have looked at me like I'm from another planet. Am I the only guy who does this?
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Old 02-13-2007, 05:49 PM
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single plane intakes produce lower vacuum anyway so if its a vacuum activated shift, yes it will suffer and shift differently than with a dual plane intake
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