Frame boxing question

[Magikal]

Getting ready to four link my rear. I know i need to reinforce the frame where the links attach. Figured i will box it in. If i go a foot or so in either direction, will that be adequate? Also, what thickness of steel should i use to do this? Probably will add a crossmember at this point also.

 

[imiceman44]

Getting ready to four link my rear. I know i need to reinforce the frame where the links attach. Figured i will box it in. If i go a foot or so in either direction, will that be adequate? Also, what thickness of steel should i use to do this? Probably will add a crossmember at this point also.

1 foot either way should be good, but don't just cut it straight, make it like fish tail, pretty much the opposite of fish plate.
You basically want to start a void in the middle and end with a wedge on either side and the void needs to be curved, no angles

 

[76zimmer]

Look at 2000 and up frames. They are similarly built in sectional boxing.