d 8 14a pros and cons

Two have come up for sale . Looking for advice from the experts thank you 

My advice to you if you want an 8 is to go find yourself a decent 36A. I think all of the parts except engine parts would be very hard to come by, I owned one for 2 years and I can tell you doing field work that turboed D7 will work it to DEATH and be easier to drive. If you want an antique it’s fine but if you want to go get some work done go find yourself a nice 36A you won’t be sorry plus if it breaks down you will dump a bunch of money in it and still have an old non turboed 8. 17afarmer

Do they have  8” or 9” pitch rails?  I think I’ve been told the 8” are obsolete, and hard to find decent used rails.  If they have very poor 8” rails, be cautious.  I think the 9” can be replaced with more modern rails?