Will it hit? Acceptable header to frame clearance

[wake328]

I have the typical areas of concern with my headers... done plenty of research and never found a definitive answer on what is to be considered a general "safe" clearance between frame and header.

I would assume that the engine moves more torsional than it does side to side.

72 C10, new motor mounts, hedman elite super duty, 1 5/8 tube

This photo shows a 3/16 drill bit can fit between header and frame


View from front

[HO455]

3/16" is a bit tight, but you have to look at how the engine is expected to move. They generally try to lift on the drivers side and drop slightly on the passenger under acceleration then on shifts it drops back down and back up. The engine as it comes up generally moves to the side a bit towards the passenger side. The passenger side is the pivot side if you will . The harder the shift the more violent the engine movement is. If your headers aren't coated it will not hurt anything to dent the tube for some additional clearance. You may even be able to dent them if coated if you are both careful and lucky. Neither one comes naturally to me.
If you run them as they are and they hit the frame regularly eventually it causes the gasket at the head to fail. The PO on my Burban just took a torch to the frame so he could use some Chevelle headers.

[Lee H]

I clearanced off 1/4 inch of the frame rail. After 10 years of abuse neither the frame or the header show any contact.

[wake328]

Thanks for the feedback. I might take it easy and see what happens...

P.S. - your build thread is pretty awesome Lee!

[Lee H]

Originally Posted by wake328

Thanks for the feedback. I might take it easy and see what happens...

P.S. - your build thread is pretty awesome Lee!

Thanks, have about 25k miles since the frame off. It’s still fun to drive and gets out multiple times a week.