K10 with fresh 358ci small block, mutha thumper cam, true dual exhaust w/glasspacks. 80 K20 update 

With out it its choking her down and killing at least 50hp and tq

@LibertyLifeStyles headers leak That's way I don't like using them. Maybe 5hp difference at the most

​​@Bill'sGarage no the other comment was right, minimum 50 hp. Headers offer 15+ hp. Just over stock

​@@billknepfel no.

​@@billknepfelsounds good. Yeah long tube headers are probably worth 25-40 lb-ft on this. Thicker 3/8 flanges on header collector and exhaust or header buddies or the aluminum style crush collector gaskets to eliminate leaks. Normally the 1/4 flange does warp and leaks as you said. But there's 3 solutions.