What is the year? If you can find them Thorley 315 are one that are specific to our vans. I found some never used once and got lucky.
Now I know some one this site has said that 2nd Gen Camaro Thorely headers will fit also on G-Vans with ease, as the 315
Jegs had header for them too, headman and I think hooker. Just not what I was looking, I wanted tri-y sense I tow with my G30.
All of these are long tube