1988 mercury 35 Hp (heavy duty lower unit)

[frobotz]

I have been looking for a 25-35 motor for my little fishing boat. This guy contacted me stating he has a 35 Hp mercury with a "heavy duty lower unit". Says they are bulletproof unlike a "normal" lower unit. Only upgrade I knew about on these were the bigfoot lowers on some of the newer motors. Anyone know anything about this? I am just skeptical since its new info to me.

Thanks in advance.