You may have a problem with those truck headers hitting the tranny,Dude.
I just finshed putting in a 406 sbc/T56 tranny in my 280zx.
Had a set of "TRI-Y" headers that fit close to the block but had to get them heavily modified. Cost me $1,200 with mufflers that stop under the car ,about where the seats are.
You can get away cheap if your willing to put in a non power assisted rack and pinion from and older Datsun,but it is labour intense,cause you have to support the engine and change the K member as well.
Dont think your gonna win this one that easily,lol