pro800 vs pro 600 engines; wich one is most reliable

The new (11-12) 8's have been very reliable. Many up here have got 2-3000 on their 11's with very few issues. The 2 injector over the 4 of the 08-10's took care of the dragon problems. There have been a few 6's burning down just like the cats because of a new learning curve of bleeding the oil pumps. They too should be a very solid motor. Had to make a wrong choice there unless you go little and wish you went big :face-icon-small-win

Well in terms of a technical standpoint the 600 would be a longer lasting motor, separate jugs,smaller bore,better rod to stroke ratio,less stressed crank,better cooling,better ring seal over time..ect ect..... its just a very good proven design that has always been a good motor over a long time period.
800's so far have been pretty soild engines with little to no issues...but still a high stress short rod monoblock design.
you want the best shot at 4000-5000 trouble free miles, get a 600, need the 800 power....well take a slight bit of risk with that. imho

^^^^^ Total agree

I am thinking a boosted 600 would be a ton of fun...