Clutch 11", 12", lever, diaphram??

[1980]

First time replacing clutch(manual), 78 gmc k1500, 350, sm465, np205. Original, I think. I'd like to get the parts before I tear it down. I'm quite aways out of town, and hopefully can complete the job without having to run to town for parts.
Adv.Auto lists both 11 and 12" to fit. What does it have now? Can I tell with out removing it? Also lists lever or diaphram covers. What should I buy? They offer Perfection brand, Good?
Thanks, (knowing things won't go smooth, but hope maybe)

 

[tRustyK5]

There is room for a 12" clutch, so you might as well get the extra holding power of one. The diaphram clutch is smoothly and has a light pedal feel than the three finger Borg & Beck style.

Look for Luk.

Rene

 

[bailey9r]

the three finger style holds better i think and the diaphragm is faster easier shifting (more carlike) note that they take a different throwout bearing. Like Rene says go with the 12 and get more holding power AND diaphragm (easier on linkage too) and have the best of both worlds