Changeover from 305V6 to 283 - need help!

[IamBrian]

First time writing on here so bear with me please. I have a 67 GMC 1/2 ton with a 305 V6 and full synchro 3-speed transmission. My V6 is burning oil and since I had a Chevy 283 V8 sitting around, thought no big deal to switch engines. I replaced the motor mount stands to V8 and bought new motor mounts for them. Of course my issue is with the bellhousing, clutch, shift linkage and driveshaft. The Chevy bellhousings are about 6 3/8 inches (shorter than the GMC I removed) and of course this moves the tranny up.
This pickup had the V8 available, so what do I need to do? I'd like to keep the three-on-the-tree shifting. Were the shift levers shorter for a V8? Any help or advice would be helpful.