Question about headers to Fit my truck after engine swap?

Ryan, I'm swapping the V6 engine in my 2011 Sierra 1500 series WT with a Chevrolet Performance 501ci / 8.2 liter with a 4L85E transmission, 3,000-3,400 RPMs stall. That entire package is the Connect/Cruise, really slick.

Question. Questions

Headers. I can find 304 stainless long or short tube headers for the 2500 series. Of course I can't find BBC headers for the 1500 series.

Fit? I understand some headers will hit the lower head bolts and that may require grinding on the header flange.

How do I find a header that will fit inside the frame rails, are they the same/similar width (1500 vs 2500)? Is it trial and error?

recommendation? Short? Or long tube? Oh, I have a 4 inch drop up front and 6 inch in back. I think there's no clearance issue. Tubes will be above the frame.

Worst case? Factory Cast manifolds, there's a Camaro type and a Corvette type that looks like it will flow better. Am I stupid to use cast manifolds? It did dyno at 614 foot pounds and 514 hp so I'd be giving up just a little. Your opinion?

Exhaust system? Planning 3 inch (or 2.5 if I go cast manifold) to Flowmaster 50 with an H-pipe dumping before the axle.



Thanks. I did watch all twenty videos where you built the 454. Great job, of course I'll donate.

My email, Krausee@aol. Com. I'd love to keep in touch with more pics and questions.

HA. The differential is being rebuilt, an EATON DETROIT LOCKER with 3.73 ratio. New bearings and hardened axles. That should handle the power.

Thanks for this website. I appreciate the inspiration of your videos.