Im not an expert on arrows but here is a little insight on your situation. Forget about the number on the arrow for right now. I am going to assume that you are shooting hunting arrows and not target arrows. Also in saying that Im going to assume you are shooting vforce arrows. Vforce 350 arrows are 8.8 GPI. You having a 27" draw length It would be safe to say you are shooting a 27.5" arrow. Just the arrow alone is going to weigh 242 grains.

Now back to the number on the arrow. The number on the arrow represents the spine. The Vforce 350 has a spine of .35. The 400 has a spine of .4. The lower the number, the more GPI. So your recommended arrow is actually lighter in this case. You will be ok shooting the heavier arrow. Makes for more kinetic energy. The difference in the GPI is only 0.7 GPI from the 350 to 400 series arrows.