Vacuum modulator on th350

[tiredtiretodd]

Just wondering, does it make a big difference where the vacuum line is connected. mine is connected to the back of my eddy carb. My brake booster is connected to the intake. From what I've read It said they should be swapped around. I also don't have a piece to my accelerator cable bracket to hold the kickdown cable in place. I bought the truck as a project and a project I got!

 

[DoubleDingo]

I think they should be swapped around. My TH400 on my 81 is hooked up to the back of the intake and the brakes are to the back of the carb. And my old 79 GMC had the brakes to the back of the carb too.

 

[firebane]

Transmission, brake booster and distributor should be hooked to manifold vacuum to work properly.

 

[MadOgre]

Yes you can use either one for the transmission line. If you have vacuum boosted brakes then the brake booster should go to the rear carb port. If you have hydro boost brakes then you can use either port for the transmission line.

The rear carb port and the rear manifold port do the same thing as they both draw from constant manifold vacuum which is what you need for the transmission line

 

[tiredtiretodd]

Thank's for the info, I'm figuring out all of the things that aren't working by tracing the lines and hoses to where they go. Next up I'll be buying a kickdown cable bracket.

 

[MadOgre]

Don't buy the Edelbrock "Universal" Bracket. It is a Piece o ****!

Ya just noticed you have a brake booster lol hooked to the manifold. I would do some junk yard searching for the correct nipple fittings for the Brake booster to go to the back of the carb and the modulator to go to the manifold.

 

[tiredtiretodd]

Thanks, yeah I went to the auto dismantler and got an original bracket off a K15 it doesn't have the accelerator cable hole in it though only the kickdown and a hole for the brake booster hose so there were definately different brackets on different year/models. Also unfortunately for me I do have a Edlebrock universal bracket that was already on there for the accelerator cable and it is a piece of crap that I will be looking for a original to replace it with.

 

[firebane]

Thanks, yeah I went to the auto dismantler and got an original bracket off a K15 it doesn't have the accelerator cable hole in it though only the kickdown and a hole for the brake booster hose so there were definately different brackets on different year/models. Also unfortunately for me I do have a Edlebrock universal bracket that was already on there for the accelerator cable and it is a piece of crap that I will be looking for a original to replace it with.

You have the old style where the hardline for the brake booster feeds through.

If you have switched to a edelbrock carb then you'll have to run aftermarket brackets but if your running the stock quadrajet then just fine the bracket for that.

 

[tiredtiretodd]

You have the old style where the hardline for the brake booster feeds through.

If you have switched to a edelbrock carb then you'll have to run aftermarket brackets but if your running the stock quadrajet then just fine the bracket for that.

So the stock kick down bracket that I bought won't work along with the seperate Eddy bracket?

 

[MadOgre]

So the stock kick down bracket that I bought won't work along with the separate Eddy bracket?

What is this separate Eddy bracket ? For throttle ?

If the kick down cable will reach the throttle bracket on the carb then you are fine if not you can get an aftermarket bracket. If you already have a separate throttle bracket then get Edelbrock #8030

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and use this as your kick down bracket. I highly doubt it will accommodate the kick down and throttle at the same time but it just might. The Edelbrock universal bracket may accommodate both but its a piece of **** that flexes like crazy.

 

[tiredtiretodd]

Thanks, yeah the cable reaches the throttle no problem with the stock bracket.