Ok. I'm a new guy here at TRS, but I have found a couple potential headers for I-Beam trucks. I did not see either of these listed in this thread. Thought I would share and see if anyone with experience has any input on feasibility of fitment for these.
First up is a set of block hugger headers that Speedway sells. The part number is 9300201S. They are 1 5/8" primary to a 2 1/2" collector. I found a few pictures of them on a British car/American V8 swap website. They look like they could work. Not sure if they might dump right onto the I-Beams. Currently priced around $270 bucks.
These look like they fit real tight to the block and may clear the steering shaft on the driver side and also the frame rail on the passenger side.
Next up are a set 351W swap headers that are also of the block hugging variety. But they differ from other block huggers in they merge into a flat collector configuration. They are also 1 5/8" primary to a 2 1/2" collector. They are made by Patriot and come in three varieties. Natural, painted and silver ceramic. The base part number is H8482 and I found them on Summit's website. Prices are currently about $275, $280 and $406 respectively.
These are the natural version and the picture shows you how they are constructed. The #4 primary sweeps back rather sharply which should provide steering shaft clearance. The passenger side sweeps back and down but my not clear the starter if not mini and may even have issue with a mini starter if used on a 302 instead of the 351W they were supposedly designed for. They almost appear to be of tri-y design. Though I doubt they could be considered true tri-y headers due to the short length.