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67_C-30 · 05-29-2006, 12:33 AM

You shouldn't have any problems. We've run as high as 11:1 engines with a aluminum heads and EFI. Aluminum heads dissipate heat much better than do iron heads allowing more CR on pump gas. Depending on what pistons you use, you are going to be a little over 10:1. The numbers below are for a 2 valve relief 7cc flattop piston, figured with a .030" overbore (which is actually a 331 cu in engine)

Compression Ratios
58-10.3
62-9.8
64-9.6
76-8.4

05-29-2006, 12:33 AM	#2
67_C-30 I have a radical idea! Join Date: Jan 2005 Location: Sweet Home Alabama! Posts: 6,513	Re: Info on L98 Corvette Heads You shouldn't have any problems. We've run as high as 11:1 engines with a aluminum heads and EFI. Aluminum heads dissipate heat much better than do iron heads allowing more CR on pump gas. Depending on what pistons you use, you are going to be a little over 10:1. The numbers below are for a 2 valve relief 7cc flattop piston, figured with a .030" overbore (which is actually a 331 cu in engine) Compression Ratios 58-10.3 62-9.8 64-9.6 76-8.4 __________________ '67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club!