Need some help with gearing and driveshfts

[84CUCV]

I would like to remove the 700/208 from my 83K5 and put on a 400/208 from a CUCV with low miles on them. I would rebuild the 700, but i just dont have the cash now. What i need to know is will the drive shafts work with the 400/208 set up. Now a question on gearing. truck has a mild 350 400/208 combo 35" tires for now till i have the cash for 38" tires. I can go with either 4.56 gears or 4.10s. With the little i know about it i think 4.56 would be the better choice. Also, how do you think this truck will do on the highway? Will be seeing some of that too. Let me know what you guys think. as always thanks for the help

 

[resurrected_jimmy]

your 400/208 combo should be close enough length wise to your 700/208 to not need drive shaft mods. 4.56's and 35's put me too high on rpm's for comfortable cruising @ 70 mph but was a great around town/trail gear. The 4.56 and 38's combo works really well on a non-OD auto

 

[84CUCV]

so on the highway think i could do 60 with lower rpms and be OK?

 

[Zeus33rd]

T400 I think 4.56-4.88 is about right w/38"tire. 700r4 I think anything taller than 35's and 5.13's are the best idea. Ever thought about a 4l80e? TH400 w/od.

 

[84CUCV]

i dont think i have the funds for a 4l80e. from what i know there is some big numbers with that trans. was going with a 400 because i have 4 of them.

 

[Zeus33rd]

i dont think i have the funds for a 4l80e. from what i know there is some big numbers with that trans. was going with a 400 because i have 4 of them.

lol, thats a pretty damn good reason. I would do the same.

 

[84CUCV]

ill keep my foot out of it.......for a while

 

[resurrected_jimmy]

IIRC I ran right around 3000 rpm at 70 which isn't terrible but my mufflers made it irritating after a few hours

 

[84CUCV]

Ok what is IIRC? thanks

 

[resurrected_jimmy]

Ok what is IIRC? thanks

If I Remember Correctly (IIRC) I ran 3000 rpm at 70 with the 4.56 and 35 combo

 

[84CUCV]

got it thanks