A 38 vanguard is the same bore as a 40 intek @ 2.97, depending on rod length is going to determine if you need to cut the piston down, but from experience I?ve seen you can bore out roughly 160 thou before to come through the sleeve, so keep that in mind and sleeving might not leave a lot of room for head bolts to bump up to the kohler/ Briggs 44 3.13+ pistons , other may know more, this is just what I?ve observed