1985 6.2 diesel opinions needed!!

[ol'blazer]

so i got a deal on a 1985 k10 with a 6.2.... or i thought it was until i got it home and the engine was blowing back into the rad... im pretty sure its a cracked head, or head gasket..

so this is my problem.. i want this truck as my DD, but i do a ton of winter driving and i wont always be able to plug in, because of my job. at the same time i like the fuel economy of the 6.2.
on the flip side i have a strong running 350 and a 305 that i could swap in... i loose the fuel economy, but im more familiar with them and they'll work better in the winter. what do you guys think?