bbc with headers can burn the boots you want them away from the headers i have only seen one set s of wire boots that can take the heat if your runing the stock tin heat shields with the headers i would take them off they were never made to take the added heat from a thin wall header. they will just be super heat the shield and burn up the boots .i used the boots you can bend for bbc a set 90 boot can work .a photo would help . i think your ok on jets and timming it is just a bbc thing i use RM wire looms and takes time to do the wires so they are not in the way of the header tubes