I have a 5.3 in my 99 gmc z71 4wd. Im thinkin about dropping in an 8.1 in it, but is it a drastic change in power and torque? Would i need to change my tranny after dropping in that engine. My truck is lifted and want to run 40's eventually and im pretty sure the 8.1 will smoke those tires. If the swap isnt recommended what would u suggest.

 

for what you are going to spend trying to do that you could build you a bad *** stroker motor. there would be a lot of work to get the 8.1 to work. it would be cool and i feel if there is a will and $$$ there is a way.

would prob go with a 4l80e also