hello all... i need some advise

i have a 4 star 60 that is not performing to my expectations with an o.s. max .61 sf . i want to put a big four stroke on it and need some help on the size. i am new to all of this and really dont have any idea what would be to big

the specs says .90 four stroke is the biggest they recommend for the plane. i am not looking for more speed really just alot more verticle

i was thinking about a 1.10 four stroke..

please give me your input on size and manufactuar

thanks alot .................................................. .......... cantw8tofly