Another torque converter question

I have a "Frankenstein" Dodge stepside pickup. It is titled as a 79, but pieced together. Engine is a rebuilt '70 340. Kickdown was not hooked up when I bought it. I hooked it up, but too late. The 727 is in the shop getting rebuilt now. I am asking advice on what converter to run. The converter I took out was stock, and practically brand new.

'79 ? Dodge stepside pickup. Weight = heavy??

Engine - 1970 340

Cam - Crane PowerMax Camshaft, hydraulic flat tappet, 3,000 to 6,000 rpm operating range, duration at .050 lift - 228 int./ 228 exh., valve lift - 0.480 int./ 0.480 exh., lobe separation - 112 degrees

Rear - right now it has a 8 1/4 open truck rear with unknown gears (3.55's maybe?) the truck is tubbed with 33 x 19.5 x 15 inch Mickey Thompson Sportsman tires on the rear. The rear is not narrowed, the rims have a HUGE offset to bring the tires under the truck. The frame is cut, boxed and moved in about 6 inches on both sides making room for the tires.

I am looking for an 8 3/4 suregrip rear with 4.30's to replace that 8 1/4.

What stall converter do you suggest? Thanks in advance, Keith.