I need to adjust the shift points on the trans in my blazer. Currently it shifts at 3500 under full throttle. I'm barely into the power band of the engine at that point. I'm swapping a set of vortec heads on with long tubes and possibly changing to a larger cam so I'd like to take advantage of the power. I was thinking of adjusting the shift to be around 5500rpm at WOT. That should drop it back into the meat of the power band. Truck is on 37s and has 3.73 gears. Thoughts?

 

There is a TV cable that comes out of the transmission and should be connected to the throttle on the Carburetor. That has to be adjusted and they also sell a adjustable modulator that bolts to the transmission that replaces the factory non adjustable one,it has a vaccum hose going to the intake manifold. B&M sells a governor spring kit with tons of different springs, you will have to play with them and see witch one works with yours.

 

I've already adjusted the tv cable.

 

350 doesn't have a TV cable. It has a kickdown cable. It's not really "adjustable" to begin with. If you have a TV cable, it's a 700.

If it's genuinely a 350, it will have a vacuum modulator, at the pass side rear of the pan. It will be one of 4 types: a big black can, or a small brass can with either a red, green, or purple stripe. If it's not the brass can type with the red stripe, GET THAT ONE. Don't even bother with any of the other types. Unfortunately you can't usually go to the parts store counter and ask for it that way; works better to find an application that's a "good runner" and then just look in the box. Might want to try something like a 69 Chevelle SS396 (same modulator fits 400, PG, & 350). Or, you could order one from transmissioncenter.net or some such. It has an adjustment in it: takes a small (1/8" or so) slot screwdriver, turning that clockwise raises shift points, you can somewhat dial it in that way, by adjusting it in ¼ turn increments.

Next thing will be the governor. It probably has SOOOOOOPER HEAVY weights in it. You can either buy a NEW one with lighter weights, or drill some small holes in the ones you have.

First thing to do though, is to positively identify the transmission. 700 pan is square; 350 pan has one corner lopped off; 400 pan looks like an oven mitt, or a distorted state of Texas.

 

It's for sure a 350. I know how to go about adjusting the shift points. I'm more curious about where I should have it shift at WOT.

 

Imo at least 5200 but probably 5500 or even higher as you said. Been a while lol.

 

It should shift the way you want it to shift. Just keep adjusting it until any further adjustment makes it shift some way you like less.

 

That was my thought. It's been a while since I've dealt with stuff so close to stock haha