[brainsboy]

Eleanore,

<<Buy different rods until you check out that they will fit>>

6.2rods on a 350stroke comes out to a 1.77 ratio

As said before anything over 1.54 or so is considered good, going far beyond this standard is really pointless and no major gains will even be seen. but without getting into all of that, and starting a major theory debate.
I dont even know if a 6.2 rod will physicaly fit. It certainly is too long for a 9.2 deck height 351w

As anouther person suggested go with a 6.125 and 302 pistons then you still have a rod ratio of 1.74