Is it nhra/ihra legal? I know it isn't as strong as Dom or 4130.

 

If it "ERW" its legal.

 

ERW is legal, but it is the cheapest, dirtiest tubing made. Basically thick fence post. Little FYI... if you run ERW tube you have to use .134 wall to get the NHRA sonic test to pass consistently. ERW has loose tolerances and the thickness is not the same through the tube.

You can run .120wall in DOM tube because the tolerances are much tighter(-.002, +.004 IIRC). This will allow you to run a lighter tube and still pass NHRA cert if need be.

You get what you pay for...

 

S&W says they recommend that over Dom because where the bends are they say it may be under .118 on the dom

 

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Do they even check the bends??
If they do, I've been very lucky, because they always do the middle of mine??

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Ive never had em check the bends, just the middle like you said.