Transmission 700r4 vs turbo 400

[kodalee]

I was wondering what the difference in the two trannys were. I have a 85 k10 4x4 that has the turbo 350 in it now. When the truck is done it will be on 37s with a built 350 and 4.56 gears. It will be mainly for playing but i still don't want it to be rough on the highway.

[zieg85]

According to my calculations your set up will run 2485 rpm's @ 60 mph.  This would be the same for a TH400.  If you opted for a 700R4 cruising at 60 in 4th OD gear would drop the rpms to 1809.  Depending on how your engine is built for the rpm running range this may be a bad thing.  More info would be needed.

[pholliday1]

Small block 37's and 4:56 gears, the turbo 400 makes more sense if you opt for the 700r4 you will find the tranny frequently "hunting" between Drive and OD, if you find the tranny hunting a lot you can always keep it in drive instead of OD. My assumption  is this small block will be making basic hp numbers if that's the case I would lead towards the 400, if this small block is a monster you can get away with the OD. 37's that's a good chunk of rubber lots of resistance.