Big: that must have been a real weak 40 as I've flown a couple with 40's and they did OK. A 46 does real well and that's what I use most of now.
As far as a 90 goes : I think you are going to have a heck of a time getting it in the cowl, in fact I would have to go take a close look at mine but I don't think it will fit. I'm sure it won't fit the mount and you will play heck finding one that will fit.
Next, if you were able to get it in, that's WAY to much engine for that plane.
Now that I've steped off the deep end, I'll go farther and say Good Luck, but I think you are blowing smoke!! ENJOY !!! RED