Anybody know the correct (original) speedo cable length for a 67 convertible small block powerglide? The trashed unit I took out was a 63" but definitely looked like it was pulled too tight. The assembly manual makes me think it was longer for conv's than coupes, but other than an outdated part number not much info there.

 

As a follow-up question, is there a way to put a new firewall grommet on the same speedometer cable once the ends have already been crimped on? Outside of repros, the cables don't seem to come with the grommet, although replacement grommets are available....