[kitcarbp]

I went to the source, I contacted the 460 SCJ crate engine head designer (Jon Kaase) for my SCJ head from Ford racing and he confirmed they use FEL-PRO # 1420 on their racing engines. I confirmed they match the ports nicely on mine. I decided to use ARP stainless studs for all but one fastening point on each side (due to clearance). I can't comment on leaks, I am still in build mode. Leak potential will depend on so many factors such as: flange material, flatness & thickness and then the stress/load the side pipe movement places on the entire 16 bolt flange which will depend on how the side-pipes join the header collector (slip joint, flange joint etc.) and how the side pipes are hung/supported from the chassis.