On my engine (New Century block) the gear drive front cover has quite a bit of backlash, I haven't actually measured it, but it's about 1° of crankshaft movement, so it's more than I'd like. It's a Fowler cover/drive and I contacted them to see if a slightly oversize idler was offered, no such luck. The only thing I can think of is to enlarge the dowel pin holes and try some .015 offset dowel pins to move the cover closer to the crank/cam. Anyone run into this before? Any other ideas? I really think that with too much backlash it's hammering on the crank and cam.