If you are still struggling to get it in you could remove the transmission mount and that would let you move the engine up and down a little to help align the dipstick tube. There is not much wiggle room trying to get them back in. Just make sure not to move the engine/transmission combo up and down to much. The fan and distributor are more than likely the first things to make contact. Sorry, I should have read everything before posting. Could be the wrong size o-ring. I have never had a problem with one going in.