[Yukon Jack]

In my 69 K20 I'm using Dynomax Cermacoated headers, part number 86022, designed for the 67-87 BBC 2WD. The headers for 73-87 BBC 4WD would not work. The engine is sitting in the small block engine crossmember using the original small block style engine mounts. To make these headers fit I did not have to make any modifications to the driver's side other than I did have to go with a shorter oil filter as this engine has an oil cooler setup which put the larger oil filter in contact with the headers. On the passenger side I had to remove a little bit of frame to give clearance for the first and second header tubes. I would guess I removed about 1/4". I also ended up grinding off a little bit of the engine crossmember tower as it was in contact with the bottom of the first header tube. I also used a 1/4" spacer between the crossmember and the engine mount to raise the engine a bit to help with header clearance. The above modifications have me comfortable with the clearance around the oil pan and passenger side headers.

These headers have 1 3/4" primaries and a 3" collector for round port size 2.1"

I'm running a hydraulic clutch and the stock z-bar would not have worked with these headers.