7 1/4 SureGrip for 1966 Valiant Resto

Standard. I do have an early 3.55 set, small bolt holes in ring gear, real early a body hyperpack and 273 I think.
I have a 66 Signet with 273 commando and just went through motot and tranny. Car has beautiful 14" 5on4 Rallyes etc so just looking to beef up the rear end to a
Posi type unit. I would be very interested in a 3:55 or 3:90 and anything in between. Are kits available to rebuild them? I live in Northern California and have been looking for a while..many claims to have them etc.
But yet to close a deal (I almost thought they did not exist) lol. Any advice and help would be appreciated, Keith