Depends on how much thrashing you're planning on, tranny etc. I built a mild 327 back in '70, went thru 4-5 single traction stock units, 3.73, 3.56. 3.08 etc. before I got smart and got a posi, ran 4.11 and 4.56 with no problems.Can a stock 55 rear end be used with a Small block 350 with around 375 HP? If not, what rear end do you recommend using?