3.75 inch(95mm) exhaust hose on to a 4 inch elbow

[candrive55]

So making do with a 3 inch merc exhaust y mating up to a chev 350 with the 3.75 inch riser outlet. I can find reducers that are 4 inch to 3 but not 3.75 to 4 inch. Can I just tighten it up or is there some kind of sleave I can use to take up the 1/4 inch.
Thanks

and oh I have not bought the risers yet. My manifolds are osco 5805. And it seems only the 3.75 inch outlet riser is for them????