If you've really "been all over it" and that's the only rust(or rust repair) you find,I'd say that's a decent 1000-1500 car.Used trannies are cheap enough,but maybe it'll work...and maybe it won't.If you know someone that can build 'em,you can get the parts to rebuild a c4 for about 100,then whatever labor they charge you.Couple more things though.Hows the hood/grill?Rust free/dent free Comet hoods around here will fetch 150-200 easily and a good,unbroken grill will bring over 100,even a gray one.Both pieces are kinda hard to find,thats why they are becoming a bit pricey.
haha yaa but since every one around here seems to be in such need of comet hoods and grills theres a yard i know of that has a lot of comets and mavericks in it ill look and see if theres anything someone might need in it