Speedometer cable

[truckbabe]

This is my very first post on here. I surely appreciate anyone's feed back.
I have a 1977 4x4 that was originally a 4 speed with a 305 transfer case. I put in a new 350 vortec with a 700R4 and a 308 transfer case. I am finally at a point where I am re-doing my gauges and while I have my cluster out I need to do the speedo cable. My question is: can I order a speedo cable for a late 80 model Chevy 4x4 automatic? I also read, while looking through other posts, that someone said the speedo cable attaches to the transfer case on 4x4's; however I thought it still mounted on the transmission. 
I could measure and go down to the custom speedo/gauge shop here in town but would rather save my money if I can just order it from   trucks. The part number I was looking at and thinking would work was 36-2030.
Thank you guys for any help or direction you can provide.

[Irish_Alley]

welcome from maryland.
typo but np205 and np208 transfercase, since you said its a 350 vortec are you talking about a 96+ 350 or a tbi 350? the 700r4 and 208 what year did they com off of and the speed sensor sould be on the outputshaft of the transfercase. this is so when your in 4x4 low you still will be reading the right speed. if you were in 4x4 low and it was in the transmission it would be off by a great deal

[frotosride]

Yes it attaches to the top passenger side of the t-case. The 2wd version has the cable and or speed sensor on the longer tail housing that the 4wd models do not have because of the T-case adapter. I can post you a pic of mine when I get out to the truck tomorrow. You can easily get away with a factory Speedo or any cable driven speedo and the OEM cable for any fullsize that came with the 700/208 combo. The length wont change because the engine, tranny and tcase will sit in the same place since all the bodys and frames are almost the same. Sont forget your lockup wiring or the 700r4 becomes a complete waste unless you don't plan on driving for long hauls and only need the low gears of the 700r4.