I want to put a 1999 toyota tundra v8 in my 1995 4x4 toyota truck

Anything can be done if you have 1-the time and/or 2- the $$$$$ and 3- Both You'd want to compare the weight of each engine, the location of the motor mounts, the possible interference with the steering components, front end parts , location of A/C and Alternator. Size of needed radiator, would your old transmission hook up or need to swap in the Tundra Trans.? Will the drive shaft need adjusting? With the extra power will the rear end be able to handle it? Will the computer of the Tundra "play nice" with the T100's (short answer=NO they are totally different critters). These are just food for thought-not to discourage your idea. Hot roders have done this kind of thing for decades. It just takes planning, perseverance and perspiration, oh and $$$ too. Good Luck let us know how it works out- you may start a whole new trend in T100 History