1100 Lift Bypass Fitting Size in Filter Housing and Bottom of Hydro?

[97SHOgt 2]

Just picked up a 520H rear end with 1100 hydro from a fellow member this weekend for my 312A with manual lift.  Working on a bypass and planned on installing a fitting with nipple on the filter housing and the bottom of the hydro.  Could not find a fitting at the hardware store or auto parts store that would work.  Does anybody know the size or have experience on bypassing the lift?  Thanks.