I seen in a post awhile back that you was thinking about going to two inch headers. In fear of upsetting anyone, I point out that I'm not saying that your wrong or it's a bad idea, just what I experienced.
In the S-10 that I raced I went from the 1 5/8 to 2 inch and it killed my torque. Just for comparision, the truck wieghed 3150 ready to race with out me in it. I had 4:56 gears, 205 in low range, 35 boggers rear, 36 swampers front.
5500 stall with trans break. Brodix heads, full roller, aluminum rods, it ran from 5300 to 7800 rpms. Even though it was stronger above 7000 I went slower.
They did sound cool though. I run 1 7/8 on that engine last year but it was in my rail, so I can't really help you compare there.
Just something to think about, maybe 1 3/4 or 1 7/8 would be something to consider. 1 7/8 or larger requires an adapter plate at the head for bolt clearance.