if moving the proportioning valve was your biggest problem then you were lucky. these swaps are easy to a point but do take some creative thinking. No way on gods green earth would i cut up $800 dollar headers. I just moved my proportioning valve, solved. I don't want to pick a fight but i don't think you saw the forest behind the tree. I am like 408 swinger, i made adjustments. I would suggest to put some heat wrap around the valve to stop any unwanted heat messing with the brakes.