I want to put a chevy 350 and I was wondering if anyone has done it. I know it can be done but how hard it is it and how fast can someeone do it if they had everything (like in a weekend)?

Ummm...no. I think someone who has done one before might be able to do enough prep work to pull it off in a weekend, but I highly doubt you could foresee every little problem (think clutch linkage, throttle cables, wiring...all those things that have to interface with existing stuff...) The hardest part is shelling out $800 for adapters on top of a chevy engine if you ask me... Or i guess if you are looking to go for an auto, get the Chevy engine and trans, but then you will need to be careful about the length of the trans you select or your driveshaft will get real short. Which engine/trans/tcase do you have now? What year is your CJ? The other thing you might look into before making this choice is building a stroker out of a 4.0L fuel injected engine. You get the same torque as a V8 with the weight of a 4.0...