I just put a 318 and 904 in my dart. wanted to use the stock driveshaft to connect the new drivetrain to the small 7.25 rear. is there any tricks for this or do i really gotto get the right driveshaft and cut the two in half and mate them. The stock driveshaft has a flange that bolts to the old transmission. is there any type of adapter or some other way to do this.

also throttle linkage....just mix and match or does anyone know of a kit.  

You need the slip yolk style 66' & up drive shaft.  so go to you local drive line repair and have sell you a slip yolk for the 904 for 7260 joint and cut and build a drive line.
this shouldn't cost more than $250.