I am fitting a 351W with a smallblock C6 in my '67, but I'm having a problem with the difference in length between the C4 and C6. Will the transmission mount and driveshaft from a 390 car work, or was there a big difference between the smallblock and bigblock C6's. Does the mount bolt into the same point on the frame? How did it fit in relation to the exhaust (I'm running headers)? I'm fairly new to this whole thing, and any help would be greatly appreciated.