Speedo Cable Help Needed

[sir_talk_alot]

ok guys, so digging into my truck this weekend, i realized the reason my speedometer doesnt work is the cable isnt hooked up. on further investigation, i figured out that the speedo cable hadnt been connected when the engine swap/trans swap my friend did because it was a powerglide and now its a t350. so i just assumed a new cable would fix the prob. oreillys and autozone were no help, they didnt have one for a 2wd. advanced has them, but he asked what length. thats my prob. he said that the new ones run about 3-4 inches longer than the old. my trucks is a 1970 custom 10 swb, its a short tail shaft turbo350, does anyone know what length cable i need? he named off a few lengths, 88 i think, 120 and 95 if i remember correctly. so i wanted to ask anyone who has messed with this what length i need. thanks guys