Which tranny should i run?

[HotRodPC]

I still havent bought a trans yet and I am still exploring my options, I went to a performance transmission shop and they asked me that they would need to know my current output shaft length so it will fit right my t case.

Hell, I dunno the exact measurments. Are they wanting the part this sticks out past the case, or the entire length or what? What T case and trans are you rugging again?

 

[1973 Chevy]

I got it figured out now, I called them out and they only want the part that sticks out. Right now I'm running 700r4/208 and from the performance one I would be running 350/208

 

[HotRodPC]

OK, so then you're going to need the setup I have on my K1500 where I cut down a 6in 2wd output shaft and used a spacer, and the 700r4 adapter. Was that this thread I posted that info up in? I think it was.

 

[1973 Chevy]

OK, so then you're going to need the setup I have on my K1500 where I cut down a 6in 2wd output shaft and used a spacer, and the 700r4 adapter. Was that this thread I posted that info up in? I think it was.

Its not going to be a simple bolt in job even with the right shaft length and same t case I got now?

 

[HotRodPC]

Its not going to be a simple bolt in job even with the right shaft length and same t case I got now?

I don't believe the NP208 will fit your current output shaft since you're curretnly set up with an NP203 right?

Before you get me to lying, we need bucket or C4 to chime in on this.

 

[1973 Chevy]

I don't believe the NP208 will fit your current output shaft since you're curretnly set up with an NP203 right?

Before you get me to lying, we need bucket or C4 to chime in on this.

No sir you must have got confused by something I'm running a 700r4/208 at the moment

 

[HotRodPC]

No sir you must have got confused by something I'm running a 700r4/208 at the moment

That's right. You're the guy with the 86 Powertrain in the 73 Right?

Then yes, for all your current dirvelines to match up, same crossmember location and all that, you'll need that adapter set up from a 2wd 6in tailshaft transmission. Then everything lines right up.

Remember when you posted that ad up for the Th350 and bucket said NO it won't work, then I caught myself and corrected bucket and say, Yeah Yeah, that is what you need along with the adapter, then I posted pics of my Th350 that replaced a 700r4. Wasn't all of that in this thread???

 

[bucket]

That's right. You're the guy with the 86 Powertrain in the 73 Right?

Then yes, for all your current dirvelines to match up, same crossmember location and all that, you'll need that adapter set up from a 2wd 6in tailshaft transmission. Then everything lines right up.

Remember when you posted that ad up for the Th350 and bucket said NO it won't work, then I caught myself and corrected bucket and say, Yeah Yeah, that is what you need along with the adapter, then I posted pics of my Th350 that replaced a 700r4. Wasn't all of that in this thread???

I think that was this thread.

I think the shop wanted the measurement so they could quote a price for a rebuild with the right output. Pretty sure places like Advance Adapters offer an output shaft for such a swap. Pricey though.

 

[HotRodPC]

I found my thread I did on this some time ago. I knew I did. Being this is likely a common swap in Squares, I went ahead and stuck it.

http://www.gmsquarebody.com/forum/showthread.php?t=1181 4x4 Swap from 700r4 to Th350.

 

[1973 Chevy]

I found my thread I did on this some time ago. I knew I did. Being this is likely a common swap in Squares, I went ahead and stuck it.

http://www.gmsquarebody.com/forum/showthread.php?t=1181 4x4 Swap from 700r4 to Th350.

Ok now it makes alot more sense to me. Sounds like the cheapest way to get my hands on one of these spacers is to search through a junkyard?

 

[Driver4r]

LOL, right now i have a th350/203 and im trying to do the complete opposite. I want a 700r4/203. Going from a 700r4 to a th350 is going to bring the rpm of the engine up, in turn, your gonna burn more fuel going the same speed.

 

[HotRodPC]

Ok now it makes alot more sense to me. Sounds like the cheapest way to get my hands on one of these spacers is to search through a junkyard?

They aren't real cheap, I think a $150 or so. I did get lucky and found mine at a Pull A Part. Pulled the Tcase off, and then slid that spacer off and was able to get the 4 studs too. As far as the shaft goes, you'd have to pull the trans and pull the trans all apart to get that shaft. So if you don't have your core trans yet, buy a 2wd Unit with the 6 in tailshaft, not a 9 inch shaft like Squares use for 2wd. Then show your builder the pics or my thread so he knows how much to cut off. Or if you can find someone with that shaft cut it off yourself. I have one of those shafts, but I use it as my pattern and incase I come across another adapter then I'd have another kit. I don't think I have another loose 2wd 6in shaft laying around or I could make you a deal. But, yes, you can find that spacer in the junkyard. This is a fairly common swap.

 

[HotRodPC]

LOL, right now i have a th350/203 and im trying to do the complete opposite. I want a 700r4/203. Going from a 700r4 to a th350 is going to bring the rpm of the engine up, in turn, your gonna burn more fuel going the same speed.

Not always true. Running big tires, you will lose more mpg running OD and tear up your weak transmission while your at it. So if you don't drive a ton of miles on the interstate, you are gaining nothing and going backwards as far as strength. Keep in mind, we're talking Trucks here, not cars. Low Rpm does not always mean higher mpg. You can turn lower rpm and be putting a bigger strain on the motor at that low rpm and burn more fuel. Truck are heavier, they are higher profile and have more wind resistance, also have bigger heavier tires to get rolling, more tire surface creating friction on the pavement, and all of these factor play a big part in mpg. If you were in a half ton 2wd stock height and tire size pick up with 3.73 or 4.10 gears, then yes I'd say for sure the 700r4 is better for mpg. Same truck with 3.08 or 2.73 gears, not the case. The OD is doing very little if anything for mpg.

 

[HotRodPC]

Man, I wish to hell I could get rockin on my truck. You know I'm converting to that A833 manual trans. I"m dealing with heater core issues at the moment. But hell, I've got the damn transmission you need in my truck and after my swap, it's going to be for sale. I built it about a year ago, maybe a bit longer. Th350 with Stage 1 Shift Improver Kit, and already adapted and ready to install with your NP208. Story of my life, timing always sucks. Shipping might kill it anyway. Being it's got that adapter kit in it, I'd probably do $500, otherwise I'd do $400 including the Stage 1 Kit.

 

[1973 Chevy]

Man, I wish to hell I could get rockin on my truck. You know I'm converting to that A833 manual trans. I"m dealing with heater core issues at the moment. But hell, I've got the damn transmission you need in my truck and after my swap, it's going to be for sale. I built it about a year ago, maybe a bit longer. Th350 with Stage 1 Shift Improver Kit, and already adapted and ready to install with your NP208. Story of my life, timing always sucks. Shipping might kill it anyway. Being it's got that adapter kit in it, I'd probably do $500, otherwise I'd do $400 including the Stage 1 Kit.

Heres another option for me, any estimating when its going to up for sale? I see what you mean with bad timing...