on a 350 tranny. is the vacuum modulator adjustable. and if it is. how do you adjust it? im pretty sure they are. but i never adjusted one. i have a high performance tranny in teh car. but the shift kit goes real fast.. so i want to hold out the shift a little longer? would adjusting teh vac mod even do anything like that?

 

To answer your questions, Yes...Maybe...and Yes.
Yes, the modulator is adjustable, if it has an adjustable one installed.
The maybe is because not all stock modulators were adjustable, so it depends on what the trans builder installed.
And yes, fiddling with the adjustment will change your 1-2-3 shift points (that's what the modulator controls in the first place).
Pull the vacuum hose off the modulator and look into the inlet nipple. If it's adjustable, you'll see a small screw slot. Cranking in on it will give you a later shift point, which is what you're after.
T-350 Modulator

 

ya what he said.clockwise =later shift point////counter clockwise=earlier shift point.it may be hard to see in the car,either take it out or put the screwdriver in it and turn till you fill it drop into the slot