t case question

[454play]

I have a 78 half ton someone put in a 454 700r4 with a full time 203 what would I need to do to go to a 205 or at least a 208

 

[HotRodPC]

I have a 78 half ton someone put in a 454 700r4 with a full time 203 what would I need to do to go to a 205 or at least a 208

WTH?? DUDE, forgive me, you've got the most jacked up combo I've heard of. NP203 and 700R4 is just wrong? How the hell did they get to that to happen, OK, with a Th350 adapter. and a 700r4 behind a big block? Let me guess, you also have 3.08 gears that I thought was uncommon in 78's? OK, enough baggin on your truck. I'm sure this is something PO did huh? Getting the NP208 behind a 700r4 is simple simple. Getting a NP205 is going to be similar to the mess they used to get the NP203 adapted. Is there a spacer in between the adapter and the NP203? If so, where is this spacer? NP208's and NP241C come with OEM 700r4 adapters in most cases if you find one on CL. I just traded one away, but usually sell them for $100 with adapter in used working condition. That is the easy way out. How long are you expecting thie 700r4 to hold up behind this 454? Do you need the OD? You might consider looking for a Th400/NP205 combo.

 

[454play]

It was all done by a PO it had 1/2 ton axles with 4.56 gears I just swapped in 3/4 tons with 4.10s I don't need the od but its nice I know the r4 won't last forever but I was told its beefed up whatever that means. If I go to a th 400 /205 will I need diff drive shafts?

 

[HotRodPC]

So you're OK with the gear ratio and strong axles. Any intent for bigger tires, like 35 or bigger? IF so, get rid of the OD, you can reasonably run 70mph with 35 or bigger tires and NON OD. You've got the axle strength, I'd look for a Th350/NP205 or Th400/NP205 combo and rock with it. All that with a 454 and some low end torque oughta make for a good toy.

 

[454play]

I'm running 35s now I'll start the hunt for a 400/205 and run the 700 till it blows thanks a lot

 

[HotRodPC]

I'm running 35s now I'll start the hunt for a 400/205 and run the 700 till it blows thanks a lot

You'd prefer a Th400/NP205, but if you find a steal on a Th350/NP205, I wouldn't pass it up either. If it's a basic OEM 454 a Th350 will hold up for quite some time, and with 4.10's and 35's a Th350 can tolerate that too. Granted, 400 is stronger but still, as I said, if it's a steal Th350/NP205, I wouldn't pass it up.

 

[454play]

If I find a th350 for the right price i would jump on it its a little more than a stock 454 maybe 400 HP tops

 

[HotRodPC]

With the right parts, like a hardened outter intermediate race, the Th350 would probably work for you. But, for sure, with that much more hp, and not only the hp this means lots of torque, in your case, for sure the Th400 is going to be the better choice all around, and for real, give up on the 700r4 in that truck. I'd be babying that dude too until you get the Th400 set up.

 

[454play]

Its not my daily so I'll keep beating it lol give me motivation to swap ir