Installed my Hedman Headers (68306 - steel, polished ceramic) on Tuesday and had the local muffler shop weld my collectors up to my dual setup (Corvette Central kit, Flowmaster 44's) on Wednesday. I had originally ordered a set of these headers in stainless steel with the black ceramic coating with an initial delivery date of late May, but that ETA became October soon after I ordered. So I changed my order to what was immediately available for my car (steel, polished ceramic) and had them sooner. Install was pretty straightforward. Only hangups were a broken z-bar clip that kept us from being able to rebuild the z-bar and reinstall it, figuring out the easiest way to lift the passenger side header into position, and learning late on Tuesday afternoon that my regular length AC-Delco #2 spark plugs were going to be too long. I am in the process of shortening my D.U.I. plug wires and changing them over to 90* boots, from the 135* ones that are in the pictures below. I've got an exhaust leak that I'm going to track down this evening or next as well. Header flange bolts are tight. I used the gaskets that were included with the headers (with a generous spray of Copper Coat, per the instructions). Pretty sure it's at a collector.

The headers will have a few chances to get hot and cure the coating before my cam and radiator swap in 2 weeks.

Installation notes:
-None of my stock manifold mounting bolts (in the heads) gave me any trouble coming out. The gods were smiling upon me that day.
-Driver's side couldn't have installed easier. Remove z-bar and spark plugs and it went right in.
-Passenger side wasn't that bad. We ended up disconnecting the idler arm from the frame to swing it out of the way, then pushed the header up and over the dipstick tube, then down into position. We did not remove the starter (factory size).
-No modifications needed to the factory AC bracket (Factory R4 compressor style).
-This spacer from Zip or Corvette Central fills the gap created by the narrower header flange on the AC lower mount stud perfectly. To hell with stacking washers.
-Collectors hang below the oil pan sump by about an inch. Plenty of ground clearance for a stock-height car. Lowered would be fine too.
-I have about 1/2" of clearance between the #2 primary tube and the idler arm (Moog K6100). We did not need to ding the tube for clearance.
-Stock-length plugs will not work with these headers and my stock heads. Had to find some Accel shortys locally.
-I will need to shorten my plug wires and convert over to 90* boots to make the routing much neater. YMMV.
-No interference between the #1 primary tube and the power steering assist ram.
-The headers clear my full-size oil filter (WIX 51069) easily, but the primary tubes run under the filter now. Oil changes in the future will be fun. Need to make a shield (aluminum foil?) to keep oil in filter from dripping onto the primaries and collector during a change.

Here are some pictures from the install and a few dumped/open header video clips.










Dont mind me. Just heading to the local muffler shop...
1980 C3 Corvette L48 Open Headers - YouTube

 

Cool. Which TBI are you running?

 

Holley Sniper.

 

I got my D.U.I. plug wires shortened up, 90* boots installed, and some heat socks installed on both sides. I'm happy with how that turned out.






Yes, I know it needs to be cleaned up in there...


After getting home from getting the collectors connected and welded up to the rest of my exhaust last Wednesday, I noticed a "tick" that I didn't have before. All the header bolts were still tight. I couldn't find any carbon checking/tracing on the edges of the Hedman gaskets (that were installed with coppercoat). Upon further inspection over the weekend, I did find 2 spots on the very top of the collector welds that were leaking. No problem, right? I took the car back to the muffler shop this morning and had them patch up the welds. Easy. But once they fixed the welds and started the car back up, the tick remained.

I'm not the best at locating sounds with my damaged ears (too many years playing drums in bands), but I'm 99% sure it is coming from the driver's side. I most likely have a leak on a bottom side of the gasket/flange near the two center primary tubes. I cant see any carbon or leak evidence, but that doesn't mean it isn't there. I've got a pair of RemFlex header gaskets for raised weld bead flanges that I will be installing tonight.

I hope this does it. I'm supposed to be giving the car a thorough cleaning and detail Tuesday and Wednesday for the club charity show on Saturday. Otherwise, I guess valve covers will be coming off...

 

I learned something else about these headers doing all these oil changes during my flattened cam swap ordeal. The primary tubes run partially under the oil filter so dropping the oil filter straight down during a change is no longer an option. The filter cant fit between the pan and primary tubes. On my 4-speed car with the stock z-bar and clutch fork setup, my Wix 51069 oil filter cannot be taken out from the side without disconnecting the link bar between the z-bar and the clutch fork. I have to pull the ear clip and front anti-rattle spring, then I can swing that linkage rod up and take the oil filter out from the side, passing over the primary tubes. The 51059 doesn't clear the linkage by about a quarter of an inch. If you have an automatic car, a hydraulic clutch mechanism, or if you use a shorter filter (like the ACDelco PF454, for example) you wouldn't have any issues taking the filter out from the side.

It isn't a huge deal to take out that clip and spring. Just a bit of a quirk for my setup.

 

Also, the "tick" I referenced in post #4 wasn't actually an exhaust problem. Turns out a lobe on my stock cam was going flat about the same time we put the headers on. Thread about that here -> https://www.corvetteforum.com/forums...-1980-l48.html

 

The best fitting headers are summit brand and the cheapest. And built better that hookers. I was going to say that thing don't sound good at all sorry