Small Block Full Length Header Options - Ground Clearance
Interesting. I'd say that's where you lost your clearance, because it's lowered.
As far as I know mine hasn't been messed with. It was difficult to get to, because it's nosed up tight to the wall and surrounded by parts. I'll try and gander at the tube tomorrow.
I know I have not had any issues with scraping, yet.. Not to say I won't, but so far so good.
Oh I know exactly where I lost clearance, that was never in question. :D My point all along has been that the Doug's headers give you as much ground clearance as is possible with long tube headers, better than even the TTI's and obviously better than anything that goes below the steering link. Ignoring ground clearance, you can see from our measurements that the Doug's headers are almost a 1/2" closer to the bottom of the frame than the ones you run. That's an extra 1/2" of ground clearance relative to the frame. Now, my car is significantly lower than yours, so overall I have less clearance. But if I was running your headers, my ground clearance would be closer to 3.5" instead of 4".
That's why I mentioned them. You can use cheap headers on cars that are at the stock ride height and not really worry about anything dragging, the car sits high enough that it doesn't matter. But if you lower the car, and you want to keep your header tubes round, the cheaper, below the steering headers aren't the best choice. And since the original poster wants to lower and autocross his car, that's an important fact.
As far as your car scraping, I wouldn't worry about it. Mine hasn't scraped on anything yet, and I have 2" less ground clearance to the header flanges. Although that is by far the lowest part of my car, it's the lowest part of the headers, lower than the oil pan, etc. From experience with my Challenger, which once sat with the header flanges 3.5" off the ground, I can say that at 3.5" of clearance my header flanges would scrape on taller speedbumps, even if I crawled over them slowly and at an angle. I raised the Challenger up so the header flanges are about 3.75" off the deck, and rarely scape on anything at that height.
