7 3/4 to 8 3/4 swap only

the width of 7 1/4 and 8 3/4 third members are different. you also have difference in wheelbase. quit possible the 340 has the larger u joint no doubt. your slant has the small ones. ya better soak the brakes lines if you will be able to take off and reuse? like he said different u bolts and mounts.

remember NOTHIN ever goes as planned.