8.8 swap

For you guys who have moved your rear back, how close is it to the gas tank? I'm in the process of finishing up my swap, and with it mounted in the center of the perch, I have 1-1/2" from the diff cover to the gas tank. If I were to move it back 1-3/8" it isn't going to leave me much room. Too I have to replace the gas tank, I'm sure that there is or could be some variances from the original tank vs a new one and I'm sure that knowing my luck it wont be for the good either. Too, shock angle, any issues? Thanks in advance for any help!