C20 69020 Header fitment issue.

[Sheetaki]

Hey guys, got a bit of an ambitious project I'm working on. I picked up a '67 C20 for cheap, and am in the process of swapping in a much more exciting motor. I bought the 1-3/4 primary Hedman 69020, as they were recommended to me by them, but I ran into a fitment issue on the driver's side. Judging from the pictures on this thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=584546
It looks like my truck has a much wider frame than a C10. That would make sense, it's a heavier duty truck, but Hedman insists those headers will fit a C20 just fine.
http://i.imgur.com/pEzsgRU.jpg
If you look at the picture of my frame rail, there's just a ton more metal there than on the picture of the C10. Doesn't help that I opted for the 1-3/4 primaries too....

So I'm wondering if anyone has these headers (or the 69010's) and has successfully fit them on a C20, or if somebody else with a C20 can chime in and let me know that I've got some weirdly wide frame or something. I appreciate any help, I jumped in two feet first blindfolded and am learning as I go .

[Sheetaki]

Going off this picture
http://i29.photobucket.com/albums/c2...ps15ae1cc0.jpg
it definitely looks like I have a wider frame. I know the truck has had it's front end replaced, hood and fenders have no emblems or holes and the grille was primer, not chrome. Is it possible that the incident was big enough that they replaced the frame, with something wider? A C30 frame maybe? Is there a VIN location on the frame? The VIN on the cab matches a C20....

[67c10rustbuket]

The issue is the year not the model (c20). In 1967 the frame channel width was 2.5" then in 1968 with the availability of a bbc from the factory they thinned out the frame from the engine stands back a ways. The frame width changed to 1.8" in this area to make room for bbc exhaust. You will just have to trim the to flange of the frame rails back a bit to clear. Plenty of us 67 owners have done it and the hedmans fit great on mine, my friends and every other truck I have seen on here. Now get to trimming that frame and back on the road!!

[Sheetaki]

Now there's an answer that makes sense! Are the frame rails thicker gauge on a 68, or did they just realize they didn't need that much metal there. The idea of modifying a the frame, on something that I will occasionally actually load up worries me. Maybe it's just more metal than needed though. Do you have a picture of yours modified? Thanks so much. I've been racking my brain on what could solve it for a good while!

[67c10rustbuket]

Here is a pic from when I thinned my frame rails. I made a few marks at 1/2" then ran a straight tape line across them. I ended on the factory radius cut seen in the pics. You may need less material removed I just tried to mimic my friends 72 frame. I also took a little material off the bottom as you can see there is an extra wide section that rubbed on my old cheapie headers. As for the gauge material used, I do not know for sure but have read here that c20/30 frames were a heavier gauge material. All trucks 68+ had the frame rails thinned like this so I would not worry about it being too weak as long as you leave the cut line straight and smooth. If you leave a jagged edge and cross cut too deep then you can create a weak spot and I have seen some questionable frame cuts. Just keep it straight and just don't take more than gm did from 68 up.

[Sheetaki]

Awesome. That's a ton of help. Thanks again for the advice. I'm so happy to have an answer finally!