[1986IROCZ28]

hey i just installed a new motor in my 86 iroc z28 the motor came used out of an 85 gmc seirra same block with just a few differences the 86 had a 1 piece rear main seal and the 85 has a 2 so the flex plate is a little different so i bought a new flex plate i now have about a half an ince gap between the flex plate and the torque converter can someone offer some suggestions on what i can do to fix the problem i still have the stock 86 700r4 with the stock torque converter anyone who might be able 2 help please do