4l60e vs. 4l80e

[laynrockers]

wanted to get some insight on the two with emphasis on my build.

I am doing a full porterbuilt kit on my 66. And i need to pull the trigger on a motor and tranny quick. My questions are regarding the size of the 4l80E and the modifications i will ned to make to clear the firewall, floor, ect. Along with my planned upgrades to see if i really need it.

The plan is a 2007 LY9 (going off top of my head might be wrong) this motor has VVT and is a great motor for gas mileage and a truck motor all in one. I need the truck motor for the accessory drive to mount the alt in the correct place.

Plans are just for a good tune, Cam, intake, 3" exhaust for now. But later on once im done hammering the truck around a while i know i will want to go with some type of forced induction. nothing crazy just looking for 400-450 to the wheels. For this HP and Tq range is the 4l80E necessary??

Thanks in advance fellas..