Oly's point about the large overbores reducing cylinder wall strength is sound advice.The small gain in displacement from a large overbore on a steet engine is offset by the structural compromise.However it's becoming incresingly difficult to find standard bore 261 engines.So many of us have to live with the bore being maxed out.The 261 in my 37 had nice bores, only requiring boring to minimum oversize. The other 261 had a 5 beautiful std cylinders ,but one was ugly and need .060 to clean up properly.Very few 261 engines are placed under the strains of constant heavy duty truck use so a big bore is probably no problem to live with if you have a decent cooling system.
Maybe one of you can explain this to me. To my way of thinking(dah),the engine heat is transferred to the coolant. Thinner metal tranfers heat faster than thick metal. So why may a thinner cylinder run hotter if the cooling system is up to the task?
