t-case/350 trans combo

[Cannaert]

A 208 will bolt up to a 350 as along as you have right adapter (4bolt to 6 bolt) and the right out put shaft spline count.
I had a older 350 that I brought that came with a 208 on it from the PO.   

You have options out there.  You can Drop the big bucks on a 205. Keep the good old boat anchor 203 get the part time kit for it.  Run a 208 or a PS drop 241 from a SAS Suburban. 

[KORNBREAD]

HHMMMMM....Im gonna have to talk to some people to see what they will charge to build my 350 to take a 208.

[Jjay78]

i got both set up's your talking about, and they both have their pluses.. the 350/203 has a lil more simplicity and you get a 2 low option.. but the 700/208 combo gets you a lot more gearing and better cruseing capabilities... you just have to set the detent right, and as for the lockup you don't have to have it, but if you want it all you gotta do is hook up the plug..with one side to a switched 30amp hot and the other to a ground and boom ya got lockup on demand

[old school truck dude]

A 208 will bolt up to a 350 as along as you have right adapter (4bolt to 6 bolt) and the right out put shaft spline count.
I had a older 350 that I brought that came with a 208 on it from the PO.   

You have options out there.  You can Drop the big bucks on a 205. Keep the good old boat anchor 203 get the part time kit for it.  Run a 208 or a PS drop 241 from a SAS Suburban. 

Just about anything you do to a 203 requires it to come completely apart and it has several hundred needle bearings in it. Youve really got to know what youre doin to put the part-time kit in it.

[ProGrade]

208 or 241 will NOT bolt right up...............because your 350 turbo is the 1970-1980 style..........meaning it has a SHORT rear tailshaft, and it was only meant to work with the 203 (which had a thin adaptor plate)..............or the NP205 (which used the thicker adaptor...but with a splined coupler inside of it).

GM did offer the NP208 behind the 350 turbo, but it was only in the 1981 model year.........and GM had to modify the tailshaft of the 350 to make that work............AKA>....they made the shaft longer..........so it would run through the adaptor.....and straight into the T-case..............this design did away with the idea of a (thin) adaptor plate............or using a (splined coupler) inside the adaptor housing.

Now you can modify a 1970-1980 350 turbo to bolt up to a 208 ( contact Mudbuster on here, he's done this already). By using a 350 turbo NP203 adaptor, with a little welding, and drilling some extra holes.....it will work. The other option you have......is getting a 2wd 350 turbo shaft....which is longer, and have it cut down to length, or keep it as is and run a aluminum spacer in between to compensate for that extra shaft length.

Other options......are     KEEP your 700R4......which should already have the NP208 behind it.......and have it rebuilt.......and have the advantage of a lower 1st gear of 3.06 and Over Drive.

Or get a 203 (very common to find) and install a part time if doesnt already have one.

Or find a NP205 for your 305 turbo, which 1970-73 (74-75 )  had fixed yokes, or the 1980 version which was slip yoke rear, and they tend to be pricey 150/250 for complete set up.

I think your cheapest route.......is to have (Mudbuster) make up a adaptor plate for you......using a 203 adaptor plate from a 350 turbo/203 combo.

according to my RPO codes my 87 has a 350 with a 208....behind a tbi 305....defies everything i've read about 208's behind 350's but its true.

[7387chevynut]

208 or 241 will NOT bolt right up...............because your 350 turbo is the 1970-1980 style..........meaning it has a SHORT rear tailshaft, and it was only meant to work with the 203 (which had a thin adaptor plate)..............or the NP205 (which used the thicker adaptor...but with a splined coupler inside of it).

GM did offer the NP208 behind the 350 turbo, but it was only in the 1981 model year.........and GM had to modify the tailshaft of the 350 to make that work............AKA>....they made the shaft longer..........so it would run through the adaptor.....and straight into the T-case..............this design did away with the idea of a (thin) adaptor plate............or using a (splined coupler) inside the adaptor housing.

Now you can modify a 1970-1980 350 turbo to bolt up to a 208 ( contact Mudbuster on here, he's done this already). By using a 350 turbo NP203 adaptor, with a little welding, and drilling some extra holes.....it will work. The other option you have......is getting a 2wd 350 turbo shaft....which is longer, and have it cut down to length, or keep it as is and run a aluminum spacer in between to compensate for that extra shaft length.

Other options......are     KEEP your 700R4......which should already have the NP208 behind it.......and have it rebuilt.......and have the advantage of a lower 1st gear of 3.06 and Over Drive.

Or get a 203 (very common to find) and install a part time if doesnt already have one.

Or find a NP205 for your 305 turbo, which 1970-73 (74-75 )  had fixed yokes, or the 1980 version which was slip yoke rear, and they tend to be pricey 150/250 for complete set up.

I think your cheapest route.......is to have (Mudbuster) make up a adaptor plate for you......using a 203 adaptor plate from a 350 turbo/203 combo.

according to my RPO codes my 87 has a 350 with a 208....behind a tbi 305....defies everything i've read about 208's behind 350's but its true.

Anything is possible.........but I go with GM service manuals and other manuals, and they all say 1981 was the last year GM used the 350 turbo in their 4x4's. Because it was replaced by the 700R4


Maybe your truck was a special order option, or despite the RPO code (provided its not an error) that 208 and 350 turbo could have been swapped in by the previous owner who had troubles with his 700R4/208 combo that 98% of 1987 1/2 tons would have come with.

[betterbeaters]

if you want a 350 that had a 208 I'll trade ya for one with a 205/203... or if you wanna buy a 205 I got one with adaptor and everything $350