th350 to sm465

[Farm boy]

I have a 86 k10 with a 350, a bad th350 tranny, and a np208 t-case. I also have a 80 k10 that I am parting out with the same setup but a np205. So I want to swap the 86 over to a sm465 and the 205 t-case and i was wondering how close the sm465 is to the th350 in length and if the rear bolt pattern is the same as the th350 so I have an idea what kind of mods to expect.

I was going to use the my6 but when I got to thinking about it the truck has 3.42 gears, and it already has 33" tires and i will be going to 35s at some point. Most of the time I will be driving within 30min of my house, with an occasional trip to Toledo (45 min) and an airsoft field (1 hour). So I figured it would make sense to go with the sm465 instead. If there is something missing in that line of thought let me know.

[bake74]

     In my 74 k10 I am going with a MY6 trans with 35" and 3.73 gears, I figure at highway speeds I will be in the 2000 - 2200 rpm range which will help a lot with my MPG. 
     As far as the swap you are talking about, the SM465 trans is shorter I believe than the TH350, so mods will have to be done to drive shaft, and you will have to install all the clutch linkage for the SM465.

[Farm boy]

using a online calculator you should be around 1,500 with that setup, and mine will be around 2,000. I think I'll go with the sm465 since i will probably be doing a lot of modding ether way, and it looks like i won't be doing too bad on rpms.

Quick question. On the sticker in the glove box it says on the tranny line: 1mxo  4 spd. auto. trans. Does that mean it had a 4spd auto or a sm465 and the auto means something else?

Here is the calculator i used: http://vexer.com/automotive-tools/speed-rpm-calculator

[Jason S]

Your truck likely had a 700R4 transmission from the factory which was replaced with a TH350 at some point.  If you were to install the SM465 and NP205, you'd have a pretty stout setup.

[Farm boy]

Well i just found a sm465 and np205 combo for $250 so i am going to get that and just sell sell mine. So why would you switch a 700r4 out for a th350? unless it was bad and they had a th350, but still. The other thing is there is a closed in hole in the floor in what sounds like the right spot and shape for a sm465 shifter, but then i don't see anything left over from the clutch petal; so i really don't know what it had.

[thirsty]

86 had a hydraulic clutch. If yours was a manual it would have a hole next to the wiring bulkhead.

[bake74]

Quick question. On the sticker in the glove box it says on the tranny line: 1mxo  4 spd. auto. trans. Does that mean it had a 4spd auto or a sm465 and the auto means something else?

     As Jason S pointed out, that means that your truck came with a 700r4 transmission.  That is the overdrive version for out trucks in the auto trans.

     If you plan to swap to a SM465, your best bet is going to be to get a donor truck that is a stick, because your truck will have none of the parts for a clutch, it will all bolt up to your truck, it will just be easier to swap from one truck to another instead of going after parts a hundred times.

[Farm boy]

Yah I agree but the guy I am getting it from has a lot of that kind of stuff or knows where to get it, and he is about 5 miles from me. That and my dad doesn't the 80 k10 sitting around any longer than it needs to (parting it out). Plus the best reason of all: I am almost wiped out from buying the second truck so I don't have the money to buy another one.

So if it had a auto tranny, what is the hole in the floor that looks like it's for a shifter?

[Fairlane514]

4WD...........transfer case shifter?

[Farm boy]

I don't think so. I will just stop describing it, get a pic, and post back in 10-15 min.

[Farm boy]

ok here is a pic of the closed in hole

[thirsty]

Looks like it is the location for a SM465 just not cut out from the factory.

In these pics you can see the factory cut out for a SM465.

[Farm boy]

It looks like it's welded, and the floor has spray-on bed liner on it. So i don't know what it is but i know that is going to be opened back up

[Captkaos]

That stamping is in most floors for pickups.

[Farm boy]

Ok i guess that makes sense. So one more question: could you guys help me out with my list of parts?
So far here is what i have:
-trans
-hydro shift bell housing
-slave cylinder
-clutch fork
Here is what i know i need to get
-clutch kit
-flywheel
-master cylinder
-hose/fittings
-clutch pedal

So what else do i need and how much of that should i get used or buy new?