Frame notching

[Z06killinSBF]

I'm in the process of notching the frame on my 66 Mustang to fit some 315's. I have narrowed it by 3/4" and am concerned about the rigidity of it now. I will be re-using the leaf springs and my thought is that the locations of the notch will become "pivots" so to say with some of the weight of the car being on the far end of the frame. My plan is to come on the backside of the notch in the location of the cut and reinforce it with some 3/16" plate. Does this seem sufficient? I hope this is clear and makes sense.

[dontlifttoshift]

You narrowed the frame rail, not notched the bottom, correct?

3/16" plate will help but not as much as you would think.

I have no education to back this up but I think a bigger concern would be the rear frame rails (where the shackle attaches) moving side to side.

[Z06killinSBF]

This is what I did. It's still in rough in phase so PLEASE don't judge.

https://static1.pt-content.com/images/pt/2012/05/ccd6989a-1.jpg
https://static1.pt-content.com/images/pt/2012/05/3fece71e-1.jpg

[dontlifttoshift]

Silly question....at this point why not just replace existing rails with box tube, say 2 x 3, and move them in an 1".

[parsonsj]

How much tire are you going to run up front? You need to be able to get a 275 up there for a 315 to balance in the back. Otherwise you'll be battling a push forever.

[Z06killinSBF]

Silly question....at this point why not just replace existing rails with box tube, say 2 x 3, and move them in an 1".

At this point I am considering that.

[MrQuick]

Silly question....at this point why not just replace existing rails with box tube, say 2 x 3, and move them in an 1".

i concure

[Rick D]

Silly question....at this point why not just replace existing rails with box tube, say 2 x 3, and move them in an 1".


i concure

I am at the same point on my Camaro I have the rail notched but down the road when I Have more power it will be my weak link, for the Camaro they make the rails so I just need move them over and I will be good. So I would say just replace them at this point it will save you not thinking about it down the road.

[Z06killinSBF]

I think I'm going to do the 2x3 and chamfer cut it to make the "S". The tire still hits the frame towards the rear because the rails flare out to allow space for the exhaust to fit between the gas tank and leaf springs (sounds safe). I'm just going to make that a straight portion and that will prevent me from having to run offset shackles.

[MrQuick]

Guys, check with Autoweld. They can bend 2x3 and still maintain strength.
http://autoweldchassis.com/spec.ivnu

But for DIY you can angle cut and fish plate no problem.