Depends on how much faster it was to start. Long risered longbows that have, relatively speaking, shorter working limbs tend to throw light arrows very fast, but they do not perform as well with heavier arrows. On the other hand, shorter risered longbows that have more working limb tend to shoot heavy arrows better, but won't shoot a lighter arrow much faster. So depending on how much faster the bow shot to begin with, it may or may not shoot faster than the others with the heavier arrow.