Do you need vacuum for a Turbo 350?

[1of1547]

I have a Turbo 350 in my Regal. I currently have the vacuum line hooked up to the pcv line. What would happen if I disconnect the vacuum? Will it function without the vacuum line? I was told that the boost pressure screws up the way the tranny shifts.

[FlyinGN]

unlike a 2004r you DO need vacuum on a T350 to make it shift.

[fc227]

Do not apply boost to that modulator. You will rupture the diaphragm, and start sucking Tranny fluid into the engine.

I Know I have done that when I first converted the olds to the turbo V6. Now that car had a draw though system so I ended up connecting it to the carb base plate.
On the FI car's I would guess you would need to use a check valve.

[1of1547]

I guess I will have to get a check valve. Does anybody have a part number of one that will work? Eventually I want to go with a full manual or a Trans brake. But that is down the road.

[Recklessrob]

Using a check valve wouldn't be advisable either.
You don't want to maintain a constant vacuum to
the modulator. Your best bet is to go with the full
manual valve body, if you're staying with the TH350.
The vacuum modulator is eliminated with the FM
valve body. :albert:

[Rickracer]

...but it would need a small, metered, filtered, vac. leak to keep the vac. from holding at whatever the max was. Man. VB would be the way to go if you're going to stay TH 350.