MARBLEHEAD – The Board of Selectmen has cleared the way for the Board of Assessors to set a Fiscal 2008 property tax rate of $8.34 per $1,000 valuation.That means that the owner of the $541,000 median single family home has seen his assessment drop by $20,000 or 3.57 percent – this year’s median home was $561,000 – but his tax bill of $4,511 will increase $158 or 3.63 percent.Board of Assessors Chairman John Kelley said, “Marblehead looks like a dog chasing its tail. Valuations are set by previous sales, sales as of Jan. 1, 2007, so they’re based on 2006 sales and some of those 2006 sales are almost two years old.”Assistant Assessor Michael Tumulty said despite that factor the values saw a minor decrease this year.The town’s overall valuation of $5.35 billion included $62.46 million in new growth, mostly condominiums and additions. Tax levy growth amounted to $499,000.On Tumulty’s and the Board of Assessor’s recommendation, selectmen rejected any tax classification factor, which would have reduced the residential tax rate at the expense of business. Selectmen also rejected residential and small commercial exemptions and an open space discount.