I know this post is really old but wanted to give my input. I have a 98 3.8 mustang 5speed with every N/A mod you can possibly to. My cam has just under .6/.6 lift and am running harland sharp 1.73's. Every since I did the cam swap (about 4 years ago from present day) I have had the exact same problem that you are describing. From a cold start up, it sounds great and there is zero ticking. But as the car warms up and the oil follows suit, the ticking gets somewhat loud. The rockers are not adjustable but have measured for correct pushrod length and used shims to get the right amount preload. One thing I was thinking was maybe the cam bearings were allowing oil pressure to bleed through and not allow enough oil to make it to the top of the engine, however this is clearly not the case for you as I assume you have a fresh motor. I have broken two valve springs within the last 4 years but it has not been catastrophic. I am running the comp 915 springs. The ticking is coming from the rocker/lifter area but I have replaced all the lifters...twice, just to be sure I didnt get a bad batch. Anyway hope this problem gets solved somehow, but I am in the process of building another motor with a new cam/pusrods/lifters..ect.
Good luch with your car, I'm sure you'll figure it out one way or the other. See ya, Will
