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					Originally Posted by  bigblockv6
					 
				 
				I had the heads ported and polished on my 478m during the build, of course the Magnum engines already have larger intake & exhaust ports as well as valves over the non Magnum engines namely all 305 and 351C engines. 
			
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 Any flow numbers by chance? 
What are the stock valve sizes for the Magnums?