I have a 1982 Datsun 4WD and im am about to lift it and put bigger tires on it.  I already know that the stock four banger aint going to cut it.  Which would be better, a V-6 or a V-8? what should i pull it from.  I would appreciate any advice.  

I had a 76 Datsun p/u a while back and a previous owner had put a Buick 231 w/ turbo 350 tranny. it was only 2wd, but it was more than enough power for that size of truck (he lifted it and put a solid axle under the front too w/ about 31 inch tires). I'd suggest a 4.3 L chevy (200 hp & 220 flbs of torque). It would fit real nice in that size of truck, and with a Painless Wiring harness you can even keep the throttle body injection. 88 and later Blazers w/ auto tranny make good donars because they had TBI and a 700R4 tranny and those have the lowest 1st gear ratio available in an auto AND an overdrive (.62:1 I believe) plus they are a sturdy offroad tranny. The only reason I say 88 or later is that the first few years of the 4.3L, and I'm not sure which, didn't all have fuel injection.  

I have a manual transmission in the Datsun now. If i did get a 4.3L Chevy engine would I have to get a new tranny also?  I think i need to get a new one anyway, because my 3rd and 4th gears grind pretty bad. And my fifth gear doesnt even work. Thanks for the advice so far, your really helping me out.  

If you were able to find a donar 4wd chevy s-10 blazer, I'd try to get the engine, tranny and transfer case all as one set.... that would be the simplest way to go, the 700R4 tranny is a great auto (lowest 1st gear ratio of all autos plus an overdrive), but I don't know alot about the transfer case. Advance Adapters makes a heck of alot of engine/tranny adapters but to my knowledge, they don't make one to mate to datsun trannys. I just checked the web site, they don't but they do make adapters to mate to toyota stuff...

I'd try for the whole chevy drive train... I'll just leave it at that.

In regards to the 4.3 V-6 for the Datson to mate the stock trans check out "Advance adapters.com" I think they will have what your looking for.  

Most people put the buick 3.8 in these trucks. your trany wont matter, you have a devorced trans case so you can use what ever tranny matches your eng just have the drive shaft made for it. I have been thinkg of use the 4.3 from an s10, and try to find a standered trany from it. I like standers. they use slave cylinders to actuat the clutch so you should be able to use your hydrolic clutch systme for that set . up.http://groups.msn.com/NissanDatsun720PickupOwners this sight is dedicated to the 720s and you can probley get a lot of help here  

MY BUDDY had a 5.0 ford and a c4 in a courier once,the 5.0 is super light and small,and at 9500 rpm sounds cool.And yes it scaired the wee out of me when he got sideways at 70,,mash that gas!