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NP203 part time kit

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Bbs383ci

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Ok, i am getting a parts list together for everything i am wanting to do to my blazer.

first order of business is to remove engine and transmission. Overhaul engine has a crate engine 350 and would be shooting to around 450hp, so ill be getting alum heads, cam and probably punch it out a little. will be using Holley efi sniper system as well.

I will be getting rid of the TH350 tranny and replace with a B&M 700r4 with around a 1500 stall.

while all this is out i would like to switch to 2 stick shifter and put a part time kit in the transfer case.

After reading people prefer to go through the transfer case and install the complete tailshaft for the part time kit.

I am having trouble finding a kit with the tailshaft, all i see is just the spider kit im guessing is what it is.

can someone point me in the right direction.

also will be completely redoing both axels and going to 4.56 ring and pinions with the overdrive tranny.
 
Let me ask, what is your plan for mating the 203 to the 700R4? The tail shaft is shorter in the TH350, in case you didn't know.
Maybe a transfer case swap would be something to consider?
 
6872xtc said:
Let me ask, what is your plan for mating the 203 to the 700R4? The tail shaft is shorter in the TH350, in case you didn't know.
Maybe a transfer case swap would be something to consider?
Click to expand...

I haven’t considered that. What transfer case to swap too?
 
Np 241 is your best bet. To get a 203 to work behind a 700r4, use the 208/241 adapter and redrill and tap the face of the 203.
 
I would look for a 241 as well, but a 208 will do most people just fine. Both have a better low range than the 203 or 205.
On a 203, as far as I know, you have to use the original adapter plate because it seals that front of the case at the lower shaft. You can either install a shorter tailshaft, from Advance Adapters, or you have to use a spacer and trim the original tailshaft a little. I did the latter to put a 205 behind a 700R4. I wish later that I had bought a NP241, however I haven't had a problem with that setup.

Depending on how you use and build the Blazer, a 208 will be fine. You just have to find a good one.
@500$k5 has a 208 in this one.

20190907_124510.jpg
 
Just find a np 241 or 208 with adapter and shifter. A lot better gearing, less weight, easier shifting, etc...
 
Bbs383ci said:
Ok, i am getting a parts list together for everything i am wanting to do to my blazer.

first order of business is to remove engine and transmission. Overhaul engine has a crate engine 350 and would be shooting to around 450hp, so ill be getting alum heads, cam and probably punch it out a little. will be using Holley efi sniper system as well.

I will be getting rid of the TH350 tranny and replace with a B&M 700r4 with around a 1500 stall.

while all this is out i would like to switch to 2 stick shifter and put a part time kit in the transfer case.

After reading people prefer to go through the transfer case and install the complete tailshaft for the part time kit.

I am having trouble finding a kit with the tailshaft, all i see is just the spider kit im guessing is what it is.

can someone point me in the right direction.

also will be completely redoing both axels and going to 4.56 ring and pinions with the overdrive tranny.
Click to expand...

I'm curious as to how you are going to get 450hp out of a 350. Sounds like closer to a stroker motor or a 400. Also be careful about aluminum heads with a cast iron block. Make sure you get some sort of sacrificial anode like what you have on your water heater at home. It keeps corrosion down to a minimum in your engine. When I rebuilt my 400, I used everything for torque down low. Heads, intake, cam, everything. I can't get that thing to knock regardless of what I have the timing set at.

Joel
norcal
 
Joel Wilson said:
I'm curious as to how you are going to get 450hp out of a 350. Sounds like closer to a stroker motor or a 400. Also be careful about aluminum heads with a cast iron block. Make sure you get some sort of sacrificial anode like what you have on your water heater at home. It keeps corrosion down to a minimum in your engine. When I rebuilt my 400, I used everything for torque down low. Heads, intake, cam, everything. I can't get that thing to knock regardless of what I have the timing set at.

Joel
norcal
Click to expand...

here’s one way to make tha horsepower. https://www.hotrod.com/articles/get-570-hp-small-block-350-chevy-pump-gas/

Any where between 400-450 is achievable for a small block 350.
 
Joel Wilson said:
I'm curious as to how you are going to get 450hp out of a 350. Sounds like closer to a stroker motor or a 400. Also be careful about aluminum heads with a cast iron block. Make sure you get some sort of sacrificial anode like what you have on your water heater at home. It keeps corrosion down to a minimum in your engine. When I rebuilt my 400, I used everything for torque down low. Heads, intake, cam, everything. I can't get that thing to knock regardless of what I have the timing set at.

Joel
norcal
Click to expand...
What? 450hp out of a 350 isnt hard. And that's nonsense about running aluminum heads with iron block.
 
Ok, wow.

ummm. What I said was I was looking for around 450hp. 400-450 for what I want, why? because this is my vehicle and what I want.

sorry about the article being for over 500hp build, I guess next time I post I’ll take the extra time to find an article that is detailed directly for the specified horsepower. You asked how I would get 450 from a 350, which makes it seem like you don’t believe it’s possible especially followed up by sounds more like a 383 or 400.

the article was for reference, if over 500 can be made 400-450 should be easily achievable and not far fetched.

I appreciate all the replies. Hopefully this next year I can start this build and will document.
 
Bbs383ci said:
Ok, wow.

ummm. What I said was I was looking for around 450hp. 400-450 for what I want, why? because this is my vehicle and what I want.

sorry about the article being for over 500hp build, I guess next time I post I’ll take the extra time to find an article that is detailed directly for the specified horsepower. You asked how I would get 450 from a 350, which makes it seem like you don’t believe it’s possible especially followed up by sounds more like a 383 or 400.

the article was for reference, if over 500 can be made 400-450 should be easily achievable and not far fetched.

I appreciate all the replies. Hopefully this next year I can start this build and will document.
Click to expand...

When I asked you how you were going to do it, I was curious as to what components you were going to use to get there. I would love to see how someone put a set of turbos or a junkyard supercharger on a small block 4x4 and made it work. It wasn't that I didn't believe you when you said you were going to build a 450hp small block. I look fwd to your build.
 
Joel Wilson said:
When I asked you how you were going to do it, I was curious as to what components you were going to use to get there. I would love to see how someone put a set of turbos or a junkyard supercharger on a small block 4x4 and made it work. It wasn't that I didn't believe you when you said you were going to build a 450hp small block. I look fwd to your build.
Click to expand...

To be honest I’m not yet sure. I’m currently searching for a 6-71 Weiand supercharger. Holleys super system can run duel throttle bodies. But it would be cheaper to build on with a junkyard turbo, now I have to do more research lol.
 
Bbs383ci said:
To be honest I’m not yet sure. I’m currently searching for a 6-71 Weiand supercharger. Holleys super system can run duel throttle bodies. But it would be cheaper to build on with a junkyard turbo, now I have to do more research lol.
Click to expand...

I know an Eaton M90 will give 7 or 8 lbs of boost on a 400 depending on pulley size. Eatons came out on Pontiacs and I believe Buicks and are only a couple hundred bucks on fleabay. Some Toyota vans had superchargers that had a electric clutch setup. Bad thing about turbos is the plumbing. I dont have a whole lot of room in my engine compartment anyways. I have seen some guys running 7.3 diesels run their intake off of the cowl right in front of the windshield which gave them a high pressure area and gave them a little bit more room in the engine bay
 
Joel Wilson said:
I know an Eaton M90 will give 7 or 8 lbs of boost on a 400 depending on pulley size. Eatons came out on Pontiacs and I believe Buicks and are only a couple hundred bucks on fleabay. Some Toyota vans had superchargers that had a electric clutch setup. Bad thing about turbos is the plumbing. I dont have a whole lot of room in my engine compartment anyways. I have seen some guys running 7.3 diesels run their intake off of the cowl right in front of the windshield which gave them a high pressure area and gave them a little bit more room in the engine bay
Click to expand...

awesome!! Thank you.
 
Joel Wilson said:
I know an Eaton M90 will give 7 or 8 lbs of boost on a 400 depending on pulley size. Eatons came out on Pontiacs and I believe Buicks and are only a couple hundred bucks on fleabay. S
Click to expand...

"Can do" and "should do" are two very different concepts here. Just because one CAN get 7 or 8lbs of boost with one of these things doesn't make it a good idea (and makes me question the understanding that the builder has of forced induction...boost PSI numbers mean little unless you're comparing identical motors, and whatever 400 it's on would likely make more power with a properly sized blower at lower PSI).

The M90 was designed for a max of 5L displacement motors, and it wasn't that great of an option on the Ford 4.6L either (which Ford figured out pretty quick on the Mustangs, and changed it out for the M112 early on). Slapping a M90 on a 6.6L motor and expecting decent power gains is going to require serious overdriving of the thing, putting it WELL out of it's efficiency range and building a ton of heat in the intake charge..which will just kill any power gains you might be getting from the boost. Spinning it at designed speeds is going to mean that it will act more like an air restriction in the intake than any kind of positive pressure delivery.
 
urbex said:
"Can do" and "should do" are two very different concepts here. Just because one CAN get 7 or 8lbs of boost with one of these things doesn't make it a good idea (and makes me question the understanding that the builder has of forced induction...boost PSI numbers mean little unless you're comparing identical motors, and whatever 400 it's on would likely make more power with a properly sized blower at lower PSI).

The M90 was designed for a max of 5L displacement motors, and it wasn't that great of an option on the Ford 4.6L either (which Ford figured out pretty quick on the Mustangs, and changed it out for the M112 early on). Slapping a M90 on a 6.6L motor and expecting decent power gains is going to require serious overdriving of the thing, putting it WELL out of it's efficiency range and building a ton of heat in the intake charge..which will just kill any power gains you might be getting from the boost. Spinning it at designed speeds is going to mean that it will act more like an air restriction in the intake than any kind of positive pressure delivery.
Click to expand...

Couple of local guys have played with smaller eatons on 6.9's. They went with eaton's to simplify the plumbing since they were stuffing these in full size Broncos. No dyno tests but boost levels varied from 5 to 9 psi depending and I am not sure what size Eaton s they used but they were out of Tbirds. They all knew they could get more boost out of turbos but the plumbing was the main issue. Fun winter project at least
 
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