First let me say that I'm new to this Chevy thing. I'm more of a Pontiac man and have a good bit of experience building these engine's, but have very little with Big Chevys, so I'm not too sure how they act, or what they like. Now my question is, I have a 454 in my 71 that is .030" over, with stock unported heads (I'm not sure the numbers off the top of my head, but they are 70-76castings), a Performer rpm intake, 1 3/4 headers, 4 speed, 3.73's, with a mechanical flat tappet cam of 284/294 adv. dur, 238/248 @.050", .567/.589 lift on a 112 LSA. This is a street strip car and I'm not sure which size of a carb I need.Depending on how you do the math, the 750 is fine, or it needs an 850/900. This is where my lack of Chevy knowledge come in, as I have no idea how this engine will want to run, what rpm range it'll want to be in, or what rpm it'll max out at. Thanks.