itow I am surprised you find the bottom end of a 351C weak?!?
Pro-stock racers have been running them with stock cranks for years????
Now if you had said 428 or 390 had crank and oiling problems I would agree.
jjoohhnnbb - 351W and 351C are two totally different engines.
A 351W is based on a 289/302 with a longer stroke.
Lots of the parts interchange between them. 289/302/351W
351W is a good street strip engine. You can build them with good torque and hp across all rpm's with little work that will run nicely on pump gas.
In 1970 the 351C was a new engine of its own that does not have any parts common with the 351W/302/289 (ok you can swap 351C heads on to a 351W but it isn't exactly a backyard bolt on)
The 351C-4V was a factory high-performance engine much like the 302 or 429 Boss with huge canted valves and huge ports and high compression making almost no torque at lower rpms and just begging to be spun to 7500rpm around an oval. Not great for a street/strip engine but with that potential to be a monster if you have the big $$$$ to build an all out motor. Personally I would rather spend the money on a nice stroker 460 although I have always wanted to experiment with a 351C with a big blower.

Force that air into those big ports instead of trying to trick it into breathing.
So to answer your question on which is better I guess it just depends on what you want to use it for.