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th350/NP203 swap into 70 K5

F

fesser

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Hi all,
My daughter demanded that the 70 k5 I'm building for her has an automatic. It was originally a SM420/dana 20 truck I believe. My donor truck was a 78 Chevy 1/2 ton. We did a part time swap into the NP203 and some work on the TH350. I kept the trans/transfer cross member from the 78 and dropped the engine, trans, and transfer case into the K5 frame. Bored some holes for the cross member to mount to the frame. Tonight we tried to put the body back on the frame. The top of the NP203 hits the floor of the body (right at the rear of the trans tunnel opening) keeping the body way too high to mount with new, stock body mounts. It looks to me like the engine/trans/transfer case assembly could be dropped a bit to the rear, but not enough to clear everything. I'm considering dropping the tail end of the powertrain and going with a body lift (which I don't really want to). I guess my question is...Hasn't this been done before, and why do I feel like banging my head on the shop floor because it won't go together? Thanks. Frank
 
You could try clocking the 203, but that would cost whatever a clocking ring costs. If you could find a 205 as alot of first gen's came with a th350 and 205.
 
I don't think clocking is going to help. The top of the transfer case is hitting the floor. I don't think the top will move down in relationship to the trans if I clock it. 205 would have been my 1st choice but I think I'd have a similar problem. Thanks for the ideas.
 
The TH350/NP205 would have been a factory setup, you would have no clearance issues.

..unless you somehow are trying to fit these into a 2WD Blazer tub with the low-rise transmission cover??? :dunno:


:usaflag:
 
The 203 is too big to fit under even the 4wd k5. I was only able to get the gearbox portion to fit by moving the engine forward 3.5 inches so it sat underneath the ridge right behind the trans tunnel.

Switch to a 205 and your problems are solved.
 
Well, Greg 72 had me all happy, and then bp71k5 bummed me out. I've got 205's here but they were behind SM465's. I seem to recall they won't work and the adaptor is hard to find. Do I recall right? I guess I should check on this stuff before I put time and money into swapping it in the first place. Thanks for your replies guys.
 
The 465 to 203 adaptors are very hard to find. The th350 to 205 adaptors seem to be everywhere around here in the wrecking yards and came stock on many blazers. I even think they make aftermarket adaptors. I sold my th350 adaptor for $25 a year or two ago, it shouldn't be hard to find one if that's the way you want to go.

Don't get me wrong, you can probably fit the 203 but you'll have to either lower the drivetrain to clear the body, cut away the body/hammer it up to fit over the gearbox, or a body lift might even get you pretty close.
 
fesser said:
Well, Greg 72 had me all happy, and then bp71k5 bummed me out. I've got 205's here but they were behind SM465's. I seem to recall they won't work and the adaptor is hard to find. Do I recall right? I guess I should check on this stuff before I put time and money into swapping it in the first place. Thanks for your replies guys.
Click to expand...

I don't see the value in swapping in a chain-driven transfercase (NP203) that doesn't fit right, when you could easily locate a bulletproof all-gear driven case (NP205) which would offer you a factory fit, and a LOT less installation hassles.

Yes, it will be a little more work to locate the correct parts, but it's less work in the long run and you'll have a stronger, better case when you're done.

We're here to help......even if sometimes we tell you things you don't want to hear! :doah::D


:usaflag:
 
All right. I'm sold. I am now looking for a 205 with the adaptor and probably a crossmember. I now have a part time 203 boat anchor.
Thanks again for your help.
 
She might...wouldn't it have the same clearance problems? She totally wouldn't agree to the 465/205 that was in there because she didn't want to learn the four speed deal. The 203/205 would get her the creepy crawly gears again.

Here's how big of a moron I am. I've got a running 73 Blazer that is my next daughter's project (3 girls, all want trucks) and it hasn't even occured to me to see what transfer case is in it. Its got unlocking hubs...205 maybe?
 
I was joking about the doubler. :)

Remembering what we did to a friends 73 blazer as teenagers, there's no way I'd let anyone under the age of 32 in the drivers seat of any of my vehicles!
 
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