Ok, so I just swapped a 350 into a v6 firebird. When I start it up it likes to stall alot or rev really high, once it warms up it will idle at 1100 in park. Once I put it in reverse it will bog down to about 400 then right before it dies it will jump up to about 1000 and then you have to press the brakes as hard as you can to get it to stay still. If you put it into drive from reverse it peels out and jumps forward even when pressing on the brakes all the way. Any idea's on why its doing this?

 

tyheres no such thing as too much power in gear lol id check your brakes to make sure theyre good and then maybe resest the minimum air, wait what kind of intake are you using? carb? tpi? tbi?

 

Well it wasn't doing this a couple weeks ago when I had it running. Its a 350 out of a 75 blazer, its running the stock q-jet but with a different throttle plate. The throttle plate is from a 79 q-jet because the secondaries on the original were rusted shut. What do you mean reset the minimum air?

 

Minimum air is a fuel injection thing. Your carb seems to need adjustment to the whole high idle and choke system. The high idle when you first start it is supposed to happen every time. Are you remembering to push the gas pedal all the way and release before starting? If so and it still fails to go into high idle and stalls sometimes then its not adjusted right. It also shouldnt be jumping its idle speed at other times.
The jerky shifting might be your tv cable adjusted wrong.

 

Yes I push the pedal down and let it up before starting. How long is it supposed to high idle for? And do I have to push the pedal again for it to idle normal or does it do that on its own once it is warmed up? I will also try readjusting the tv cable again tomorrow.

 

As its warming up, when you hit the gas again it's idle rpm will drop down a little at a time in a couple steps. I've never really thought about how long it takes since I always have the rpms higher as I'm driving away. Id say maybe a minute or two before it can drop down one step, and maybe five before it reaches its final idle speed.

The car started as a v6? What model carb is on it now? By stock quadrajet do you mean stock from the 75 blazer engine?

 

Ok, those steps sound like what mine does, takes about 10 minutes of starting and letting it idle a little before it will idle without dying, so clearly I need to readjust it. Yes the car started as a v6, yes the carb came on the engine from the junkyard. I find the model number when I get home tonight.

 

Possible loose or broken motor mount? I've seen engines rev out of control when put if gear with a broken motor count. The engine will attempt to torque over opposite the direction of rotation on the crankshaft. If the motor mount can't hold it in place, it can put tension on the throttle cable, thereby opening the throttle plate. Result, having to try to hold the car from moving by standing on the brake pedal.

 

I checked the motor mounts, they are tight and unbroken. I adjusted the timing, its at 8* btdc, and I did a little tuning on the carb. It starts and idles good now, but when I put it in gear it still jumps about a foot forward, and is pretty hard to hold in place. I filled the transmission the other day but I do not have a dipstick, could overfilling it cause this?

 

Mines always jerked like that too, but never bad enough to overpower the brakes. What rpm is it at when you shift? I'm still wondering if your tv cable is adjusted right. Even if you did the procedure with the clicks properly, unless your bracket is for a 700r4 car (I imagine that 75 engine's bracket is designed for a th350's kickdown cable), your cable may be held in a position where its out of range of proper adjustment.
I've heard of people switching to higher stall torque converters to stop the problem.
I dont know if overfilling would cause it, hope somebody else responds to that.

 

Its at 1000 rpm when I put it in drive, any lower than that and it idles really rough. I looked at summit for the geometry correct bracket and the one that came up didn't fit. I've been looking around but couldn't find any that look like they fit, any ideas on that? Also I played around with the tv cable since adjusting it the proper way didn't seem to fix the problem, and it lessened the jerking a little bit, but I don't know how it will shift on the street because I didn't get a chance to test drive it yet.