Dedicated to the Promotion and Preservation of American Muscle Cars, Dealer built Supercars and COPO cars. | 
	
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			#21  
			
			
			
			
			
		 
		
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			I don't have any spark knock problems with either of 2 L78s running premium. 36 Degree total advance.
		 
		
		
		
		
		
		
			
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	"Knowledge is good" Emil Fabor 67 L/78 Camaro SS/RS H-H,1W,2LGSR,3SL,4K,5BY. (Sold) 70 L/78 Nova M-21,Black Cherry,Sandalwood Int. 09 Pontiac G8 GT Premium,Sport,Roof. Liquid Red.  | 
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			#22  
			
			
			
			
			
		 
		
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			I would never deface a set of 840 or 291 heads by installing exhaust seats unless they were sunk, and only then I would install custom made small ID seats machined to size along with a one piece solid bronze guide honed to size with a very precise valve job, which would run easily on unleaded gas.
		 
		
		
		
		
		
		
		
		
	
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			#23  
			
			
			
			
			
		 
		
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			FWIW,My engine builder did note that a lot of L78/L72 engines that get rebuilt don't actually get to 11:1 when completed, for whatever reasons (head gaskets etc.) I know that my L78 will ping/detonate with straight pump gas (stock everything basically, timing all in at 3k) It seems to run best on a mix of Cam2/Avgas and 93 pump gas
		 
		
		
		
		
		
		
			
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	70 L78 Nova Fathom Blue,Bench, 4spd, F41, 3:55 71 Porsche 911 Targa  | 
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			#24  
			
			
			
			
			
		 
		
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			Love the smell of cam2!
		 
		
		
		
		
		
		
		
		
	
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			#25  
			
			
			
			
			
		 
		
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			<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JRSully</div><div class="ubbcode-body">FWIW,My engine builder did note that a lot of L78/L72 engines that get rebuilt don't actually get to 11:1 when completed, for whatever reasons (head gaskets etc.) I know that my L78 will ping/detonate with straight pump gas (stock everything basically, timing all in at 3k) It seems to run best on a mix of Cam2/Avgas and 93 pump gas </div></div> 
		
		
		
		
		
		
		
		
	
	Sounds like a good combo to me Sully. That is a really good running car you have and you show it NOT much mercy. Love it!  | 
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			#26  
			
			
			
			
			
		 
		
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			You are correct Sammysan, It's gets wrung out regularly, but the relatively skinny 225 14s keep it from breaking anything for the most part
		 
		
		
		
		
		
		
			
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	70 L78 Nova Fathom Blue,Bench, 4spd, F41, 3:55 71 Porsche 911 Targa  | 
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			#27  
			
			
			
			
			
		 
		
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			that is the way to do that Jim. smaller, skinny tires = smaller, little breakage.
		 
		
		
		
		
		
		
		
		
	
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