I decided to split off the info on the '78 312 into this thread. It has taken a different direction than I anticipated.
This 312 is quite nice and I think lyall took care of me. Ok, he was real good to me.
The '78 312 arrived home and my dad and I could not leave it alone. Swapped in the good battery from the 120 to see if it would turn over. It did and it was strong. Just for giggles we sprayed some MAF cleaner (because that is what I had handy) into the carb but it did not fire. Checked the points and they were stuck together. After a bit of cleaning and checking the gaps we had strong spark. With a bit of gas into the carb thru a hose we cranked it over and it ran. No smoke or funny sounds.
One thing I noticed is that the '78 does not have the front hydro lines but the '77 does. Also, the input shaft on the pump is bad on the '78 and good on the '77. Looks like these two will get morphed together into a machine I will call the Frankentwelve.