Do square body 454 headers fit?

[Chillin Dylan]

NOPE. DISREGARD THIS POST. READ MY NEXT POST. SORRY!

Here's an update for you guys. It's been a long summer but I just finally swung the 454 and NV4500 back in the chassis last night. The headers fit GREAT! Definitely recommend buying these for less than $200 rather than the ones listed for this truck that are $800 plus. Only things you need to be aware of are this. I have the rough country 4-6" lift and the drivers header clears the front diff and driveshaft perfectly fine. Can't guarantee the same would be true with stock suspension, but it looks like it would be based on the angle of the dangle and all that haha.

1: You will need to grind little notches into the header flange to clear some of the head bolts.
2: You will need to drop the starter to get the passenger header in, but the header does clear the starter itself. Just have to drop it to have room to get the header in.

Also, my drivers header slips down in easy, but my abs module is gone. So that could possibly get in the way

 

[Supercharged111]

Got a pic of diff clearance?

 

[Chillin Dylan]

Okay so unfortunately the headers don't fit as well as I thought. The drivers side header needs a slight modification. When I initially held it in there it looked like it cleared the diff well. However, perspective is a crazy thing sometimes. What looked like a good fit from the engine bay, turns out to be not so great looking from underneath. I had my girlfriend hold the header flange against the head while I went underneath expecting to get a picture of the wonderful fitment. What I found instead was this.

The collector is directly in the path of the front driveshaft. Now, I did notice that if I kept the top side of the flange against the head and moved the collector towards the drivers frame-rail... it didn't take much of an angle to get clearance for the front driveshaft. SORRY ABOUT THAT. Jumped the gun a bit on posting in here.

So my plan is going to be to make a pie notch in the top side of each runner near the flange and bend it that way to get the clearance. It won't be hard or time consuming, just know that these headers will require some modification to fit a 4x4 truck. I'm guessing they would fit a 2wd (or a 4x4 with no front driveshaft lol) just fine.

I'll update this thread when I've gotten the headers modified and bolted up, but that's not going to be for a couple weeks probably. I've still gotta do a few other things before exhaust is the top priority. Holley sniper wiring and install, set the pinion angle and weld the perches up on the 11.5 AAM swap, calipers+rotors+pads+hoses all around, etc... There's a little laundry list, but it should be driving by the end of the month. That's the goal anyway. Wish me luck!

 

[Chillin Dylan]

Well guys, I ended up finding a set of Hedman headers that fit for less than $300 on summit. I got those and they fit great. They are specifically for a GMT400 2500 4x4. I'll just leave the square body ones on the shelf for a future project if I can't get 100 bucks out of them. As far as I can tell, these Hedman headers are a new product, because I researched for almost 2 weeks earlier this year before I bought the square body headers, and could not find anything for less than $600. Here's the part number: 69390 and the link: https://www.summitracing.com/parts/hed-69390

 

[ralmo94]

Well guys, I ended up finding a set of Hedman headers that fit for less than $300 on summit. I got those and they fit great. They are specifically for a GMT400 2500 4x4. I'll just leave the square body ones on the shelf for a future project if I can't get 100 bucks out of them. As far as I can tell, these Hedman headers are a new product, because I researched for almost 2 weeks earlier this year before I bought the square body headers, and could not find anything for less than $600. Here's the part number: 69390 and the link: https://www.summitracing.com/parts/hed-69390

Does the temporary paint have to be removed to paint them with hi temp paint?

How are they holding up?

How did you route your driverside pipe, did you run it straight back, or cross over to the passenger side?