mating a SM465 to a np205/203 doubler

[MountainJeeep]

is this as easy as bolting it all up? or in my newbness, am I missing something critical?

 

[tRustyK5]

Need a SM465 to NP203 adaptor and ther correct 10 spline input gear for the NP203. Then it'll all bolt up. Of course you'll also need a doubler kit from NWF, WMS, or whoever else you might choose.

Rene

 

[sled_dog]

if you use a 10 spline 203. Could get a 27 spline output shaft from NWF and run that with a TH350 203. If I ever get tired of the slushbox this is the route I will take.

 

[u2slow]

You can do a little more work for better strength...

You can use an 81+ SM465 from a NP208/241 application. Add to that a 32-spline NP203 (Th400 type). The extra work is drilling/tapping the 6-bolt pattern on the face of the NP203.

 

[MountainJeeep]

Thanks guys. This Chevy stuff is all new to me. Basically what I want to do is run a 4:1 doubler behind the 465 which will be mated to an 87-91' 350.

That way I can take full advantage of the 6.??:1 gear ratio that the 465 has and still be able to slip from 4:1 to 2;1 as necessary. Also gonna triple stick it for as much versatility as possible.

Now for a follow-on question. I plan on usin this rig to drive to trails and also be able to handle the toughest Colorado has to offer (indy, Buena carnage, and Billings), so will 4.10 gears in the diffs be a good choice or should I drop down further to the 4.56-4.88 range? i dont want to lose to much I-70 mountain climbing ability. Think Floyd Hill at a minimum of 65 mph with a fully loaded rig :-)

Bill

 

[sweetk30]

we need lots more info on your rig to tell you what gears are needed. give use the specs.

 

[6.2puller]

Now for a follow-on question. I plan on usin this rig to drive to trails and also be able to handle the toughest Colorado has to offer (indy, Buena carnage, and Billings), so will 4.10 gears in the diffs be a good choice or should I drop down further to the 4.56-4.88 range? i dont want to lose to much I-70 mountain climbing ability. Think Floyd Hill at a minimum of 65 mph with a fully loaded rig :-)

Bill

I have a SM420/203/205 in my rig with 5.13s and it is not streetable even with the 39.5. Basically the 4 speed becomes a 2speed high or low.

I am currently building another heep for my wife and it will be 350,465,203,205 with 4.10s and 36s. Her rig will remain streetable but still be able to hang along with me and the guys if needed.

You may be able to swing 4.56s or 4.88s if you are going with a 38" tire or so but with 35-36s you wont want it that tall. You can always throw the 203 in low if you need some umph.

 

[u2slow]

I found 4.10s were too short for highway travel with the 465 trans & 33's. 3000+rpm all the time.

You'd probably be okay up to 38s with those gears so long as you had the 203/205 combo.

 

[MountainJeeep]

Gonna roll with 37-40" tires depending on what deals I can swing.

ok, for those who missed my earlier post.... to rehash the plan for my build here you all go

1987-1991 Suburban with a 350. I doubt I can score a 454 for my purchase price of no more than $1,000

37-40 inch tires

dana 60 front with detroit

14b rear with detroit

crossover steering

hydro assist

4-6" spings (havent decided yet) from either tuff country or BDS

sm465 tranny

205/203 triple sticked doubler for 4:1

I will either exocage the rig or build the cage on the inside. i am leaning toward exo to attempt to preserve the body for as long as possible.

Thanks all,

Bill

 

[tRustyK5]

You can do a little more work for better strength...

You can use an 81+ SM465 from a NP208/241 application. Add to that a 32-spline NP203 (Th400 type). The extra work is drilling/tapping the 6-bolt pattern on the face of the NP203.

That'd be OK in a Sub, but for most K5's that would be a brutally long combo. The 32 spline 465's had a pretty long output and adaptor...

Rene

 

[u2slow]

That'd be OK in a Sub, but for most K5's that would be a brutally long combo. The 32 spline 465's had a pretty long output and adaptor...

Good catch.. it is longer. The later 465/208(241) adapter is ~8" long. From pics, the 465/203 adapter looks like ~4"?

 

[MountainJeeep]

U2Slow...you have a write up for that?

thanks

Bill

 

[u2slow]

Sorry, no.... I've studied the parts in great detail though!
Its the same modification to put an NV4500 and 203 together. Just pretend the 465 with the 208/241 adapter is an NV4500

http://www.coloradok5.com/forums/showthread.php?t=127434

To mate a np203 to nv4500. You have to have a 32 spline input on the 203. Ditch the adaptor for the 203. Plug the adaptor mounting holes w/ allen set screws. Stake the screws a punch to lock them in place. Mount the 203 straight to the back of the nv4500, using the round bolt pattern of nv4500. Drill & tap new holes. 1 hole will need to be modified,(if looking from the rear upper right) moved inward towards center. Hope this helps Ed