Would anyone know what size (width,grear ratio, posi?)rear
end would be in a 58 chevy convertable. I have been offered
it power trane for a couple hundered dollars..the body is
finished...

John, I measured my rear backing plate to backing plate, it's about 54". According to my book, the '58s had 4:11 for the overdrive; 3:55 for conventional; 3:36 for powerglide and turboglide. Sorry, no info on posi. Hope this helps somewhat.
phil
--
One man's treasure is another man's trash.