Hey guys, I need some serious help. I have a 89 firebird that used to be a 2.8 v6, but I swaped that out for a custom 355 V8 pushing 400 horse. Behind that I have a B&M holeshot 3000 stall converter, and a fully rebuilt
th350 tranny. Ive put alot of time into this car and when I finally get it on the road my motor wont go over 3000 rpm when it is in gear. If it is in park it revs up no problem, but when I am driving on the street in any gear it wont go above 3000. I live on gravel roads and have an open rear end, so the wheels should be spinning out of control when I mash down on the gas, but they hardly break loose. I can't even to a burn out on any kind of pavement.

What do you guys think it is. I think it may be the converter. Any help would be great.

 

I think you are correct.

 

Maybe its the knock sensor? Did you use one for the 350, or use your old 2.8 one. If you used the wrong one it would see knock when there really is none and pull timing like crazy.

 

...checked for vac leaks? Checked timing? Checked plugs(air fuel off)?
what ignition system are you running?