Update time; got my Black Bear PCM in, and the truck runs like a hot damn now! I need to buy all the block off plates for the EGR, and possibly start making choices for opening up the exhaust; Hedman or Gibson shorty headers, delete the catalytic converters or replace them with some high flowing ones, and finding some 3" tail pipes.
TL;DR: Here's a bunch of tips for Gibson header install
I don't know if you've seen, but I have Gibson shorties on mine.
For our trucks, the driver's downpipe does not have the O2 bung welded into an ideal location. You can't get the sensor in and out with the pipe in. Furthermore, I believe there was an interference issue with the driver's downpipe too, so I had the exhaust shop cut up the new one to put joints in the right places. I also do not have catalytic converters, but I've heard (FSC.com?) that our cats are more than large enough to support 400hp. Your choice if you want to shell out $ for cats.
I had the rest of my exhaust fabbed up when I put my headers in. They didn't line up well to the old system, so I got to drive this sucker with open headers through town to drop it off. Turned a bunch of heads.
I don't have any other info on the hedmans, but I have the titanium coated gibsons. I can attest that my underhood temps aren't that bad with that coating applied. Its been 3-ish years since I've done it, and there's just a hint of rusty freckles starting to form. Per gibson, if they show up, just hit it with green scotch brite and that'll protect the coating but keep your headers nice and purdy. Also per gibson, before firing up the engine, spray down the headers with brake cleaner. Oils from your hands/engine will stain them and it can compromise the coating.
When you go to take the stock manifolds off, you'll break studs (if you haven't already got a couple broken) if you don't use heat to take them off and out. I used oxy-acetylene with a small torch tip (like a jewelers torch) to heat the nuts then tapped the threads with a candle stick. The principle is the air between the nut and stud will rapidly cool and draw the now liquefied wax into the threads and will lubricate them. The wicking action of the rust will also coat the rest of the stud. After doing this, reheat the nut a little and you can zip it right out off of there and not snap anything. I would also soak every joint you plan on touching with Kroil (You can get it at Oreilys) even if you plan on using that wax trick.
After the manifolds are off do the same trick to get the studs out.
When you go to put the headers on, there are head bolt heads that interfere with the gibson header flanges, you'll have to grind/file away at that spot to get them to fit.
I also used ARP studs with 12pt nuts to snug it all down. Heres a PN: 100-1403, or for regular 6pt nuts: 245-1311
Here's some wrench sizes too:
Manifold stud nuts: 9/16 socket and wrench
Stud: 1/4" wrench
Collector: 15mm deepwell
Double pipe Flange between cats: 17mm nut
ARP nuts: 7/16 12pt
My exhaust is built like this: 3" downpipes to ball/socket flanges, H-pipe with straight runs of pipe with magnaflow glasspacks to ball/socket flanges, 3" necked down to 2-3/4" (for proper backpressure for <350hp) to 4" tips. I make a lot of racket when my foot is in it, but I can sneak up behind my wife in the neighborhood when she's out walking.
And I would also get some DEI spark plug wire boots to keep them from getting too hot. I have Taylor silicone wires and they should be fine... but just in case I put boots on them.
Any questions?
