I also have a 68 that will never be sold ( family car) and I have the original motor for it but for now I am putting in a built 350 and keeping the original 327. I agree with what the others have said in keeping the original setup, go and research a few ways to preserve the motor if you don't plan on using it right now. If you do decide to perform the rebuild do plenty of homework ahead of time and built it right the first time so you can enjoy it, they can only be original once and the motor can only be rebuilt so many times if its not being taken care of. When I drove mine with the 327 it was a blast, when I finally tore it down I had found bits of the plastic original timing gear set in the bottom of the oil pan, never know what you will find. I cant wait to get it back on the road.

 

 

FWIW I have a 283 that has been sitting 30 years. I filled it COMPLETELY full of oil. almost to the top of the dip stick tube. loosened all the rocker arms and turn it over about twice a year