Alright, there's major controversy on whether or not the initial lt1 were internally different. Some say the lt1s with 1.46" valve springs have the hardened pushrods and 4 bolt mains. Some say the valve spring ID is different some say not. Some say only the firehawk had the hardened "pinks" rods. Others say the 1.46" valve springs means hardened pushrods and 4 bolt mains caps. What do you guys think? if so this would make the power and power ranges be different from the stated 275 at 5600 rpm. What do you guys think. I want all opinions but especially those of us who have been inside these motors. Thanks again fellow enthusiast.