The rear seal is a one piece , and larger than 2 inches , you might have the front seal , the real seal presses in like a late model 5.0 , into the block , the seal is the same as a 2.9 and the 4.0 along the the front seal being the same , the new one will be red , the old one is black and probably cracked up with old age, if it smokes when you first crank it up the vale stem seals are gone also , but just change all the seals and do a valve adjustment , these will run forever , might as well put a few dollars in it and keep the handy thing