Anyone have experience with TTI race headers built for 572-13 heads on an RB, but used on a B block with B1 heads? I will be using an AlterKtion front suspension in a 1969 B body. TTI says the 2 1/8 - 2 1/4 stepped RB headers w/ 4 1/2" merge collectors won't fit, although they sell B-block B1 headers in 2" - 2 1/8" step. I think the motor needs (and Koffel's says) the size to help make 1000 NA HP. TTI says it would be like $3500 for a custom set, which seems lime a lot, vs $1300 for the RB race headers. I like TTI headers and would rather use those than build custom. Thoughts?