Assumig you have a SBC like I have in my '62 c-10, the stock cast iron headers won't work because the torsion bars are right below the dump on the headers. Long runner headers won't work either because they dump, yep, right onto the torsion bar (trust me, I bought a pair of '69 chevelle headers thinking they would work, Not). I don't think you will get responses to your post which will definately tell you a name brand and part no. that will fit a long runner header, since I did the same thing a year ago and got nothing.
I wound up with a pair of block huggers from summit. They don't leak. also, if you are using side engine block motor mounts, that is also a problem. I have braided stainless steel flexible pipes just after the headers which I think relieves some of the header strain and keeps them tight.
