TH350-700R4 mated to NP208

[Ashton84W]

Well the governor gear didn’t fix it and the new vacuum modulator had no change. Time for a new tranny then Wanting to get all things sorted out before I pull and put in.

305/350 combo with an N/P208 in an ‘85 K10. Either gonna do a straight 350 swap or go all out with a 700R4 and have overdrive. Its been asked before but I’ll ask it again....


How can I tell if my truck originally came with a 700R4? I have Overdrive, Drive, 2nd, and 1st on my dash which leads me to believe somebody changed it along the line and the 700R4 was factory.


If I believe correctly, the 700R4 is 2 inches longer than the TH350 meaning it has a different spacer (or adapter) between it and the transfer case. I’ll need to get the one for a 700R4- N/P208 combo if I go this route correct? Anybody know the actual name of it and or where I could get one from? Tranny shops have them?


Spline count... it’s the same on an N/P208 as both the 700 and 350 right?
Or is the input spline count different on the transfer case from those on the transmissions. Bit confused on these^^^


Shifting bracket. Do I have to change anything with that? Either the bracket itself or the rods?


TV cable- big one. Am I able to connect it directly to where the detent cable is now on my edlelbrock 1406 or is the bracket geometry off? Looks like it would be the same but yeah.


Plan for this overall is to not have to do any cutting, drilling or fabricating of any kind. If I can keep the tranny crossmember in it’s place then that would be the best. If not possible then I’ll just do a simple pull and replace with a 350. Thanks for the help guys, defiantly need it. Here is a pic on my current set up. Blue arrow it the adapter I’m referring to...

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[1987 GMC Jimmy]

It sounds like it did come with overdrive. You can look at your RPO sticker, and if you have the codes MD8 and MXO, that means it came with the 700R4 itself and “provisions” for it, respectively. You’ll need to get a TV cable geometry correction kit from Edelbrock. You can probably order it through your local parts store pretty easy, though, and it’s a breeze to tack onto the carb linkage. I could speculate on the rest, but I’d rather stick to what I know and not talk out of my ass on this one. This and the reverse of what your trying to do is a very common swap so there’s a plethora of info out there.

 

[Ashton84W]

It sounds like it did come with overdrive. You can look at your RPO sticker, and if you have the codes MD8 and MXO, that means it came with the 700R4 itself and “provisions” for it, respectively. You’ll need to get a TV cable geometry correction kit from Edelbrock. You can probably order it through your local parts store pretty easy, though, and it’s a breeze to tack onto the carb linkage. I could speculate on the rest, but I’d rather stick to what I know and not talk out of my ass on this one. This and the reverse of what your trying to do is a very common swap so there’s a plethora of info out there.

Appreciate it. I figured the geometry would be off but just wanted to see. Thanks for the codes I’ll look tomorrow. PRO sticker is pretty faded though so it’s not gonna be easy. And yeah there’s defiantly a lot of information with it, sorting through it though is what’s getting me.