Last year’s winner I Am Maximus heads to Aintree on Saturday bidding to make history. Here is a look through the chances of all 34 contendersThere was a lot going on in the spring of 1974. Abba won Eurovision, Manchester United were relegated and Red Rum became the most recent horse to win the Grand National under what was then the top weight of 12 stone. Just over half a century later, last year’s winner will attempt to emulate the greatest Aintree hero of them all and defy top weight, and though he is higher in the ratings, he won so readily 12 months ago that he would surely have done so with another 8lb on his back. Lacklustre in two runs this campaign but Willie Mullins will have been working backwards from here and he seems highly likely to leave that form behind now he is back at the scene of his greatest triumph.Verdict: classy acceleration to seal victory last year, big chance to repeat from 8lb higher markVerdict: top-class at Haydock and when the mud is flying. Will not have either hereVerdict: loves spring ground and in the mix, but worse off with a couple of rivals on recent formVerdict: decent form already and best days still ahead of him but not cut much slack by the handicapperVerdict: the 2023 King George winner will love the ground and the trip but might lack a gear-change when it mattersVerdict: big run last year and can’t get classier than a Gold Cup winner but may have missed best chanceVerdict: outstanding novice over hurdles, yet to show same form over fences or at an extended trip&