[IMPALA MAN]

I'm sure no one thinks of this however it needs to be considered ANY TIME you change cylinder heads. Anyone who has done a 1st Gen Camaro with a steering box or any other non-rack and pinion cars, knows that header to steering box interference seems to always be an issue. That being said, it is critical that you make sure you will have clearance with the new heads. Why would there not be the same clearance you ask? Because not all cylinder heads are the same dimensions. Anytime you stay with factory heads you are pretty safe. When you start getting aftermarket (especially aluminum) heads, you should check first. If you have plenty of room around the steering box, then no need to worry. For reference, the most difference I have seen from factory to aftermarket, is around 5/8" wider per side. This means the header will be 5/8" closer to the steering box and 5/8" closer to the factory A/C box. Nothing is worse than getting the heads installed, engine dynoed, installed and then the last thing, installing the headers only to find out they don't fit. This is not a statement suggesting that ProFiler heads are wider. It is a post suggesting that whatever brand you go with, to check first. For reference: if you measure across a Small Block Chevy with factory heads it should be right at 18". This measurement is taken across the front of the engine at exactly the left and right front header bolt holes. If you measure below the header bolt holes it will be less. Above, and it will be more. The surface where the header bolts to the cylinder head sets at a 5 degree angle.
Best of luck on your cool project and feel free to PM me if you need any additional information.