typical rearend ratios?

[streetstar]

my truck is a 69 and has a 307 with a th350 -- no other options listed on the SPID related to perf./towing/posi-trac. etc. -- so i assume it has base model, peg leg gears--

i do know that this can vary, but does anybody have an idea of what typically was installed in the rearend of a combo like this?

(its rainy today and i'm bored, but i dont feel like rolling in the mud to pull the diff cover today)

reason is i will be doing a 700r4 conversion sooner rather than later, and trying to determine if i will need to change the diff gears too