Its a drag car but I guess my questions are a little too much for this place. 2x3 up front, maybe on your car but thats a little too weak for my goals. Maybe you should get a bigger pic in your SIG.
Nobody.
Let me say that again so it'll soak in.
NOBODY has ever built a drag car using 3" round tubing on any part of the car, except exhaust tubing, and that is what that tubing is intended for.
Unless you are building a Monster Truck.
But then you aren't building a Monster truck now are you?
Dude, do yourself a favor, and get a chassis manual.
You'll see that every drag car ON EARTH is built using a combination of either 1-5/8"-1 3/4" .125 .134 wall mild steel for roll bars.
OR
1-5/8" Chromoly where the wall thickness is allowed to drop to about .090.
OR
And 2x3" .125 wall rectangular tubing for frame rails/ SFC's for those.
Here's a little tidbit for you to gnaw on:
The current 25-1/2/3/4/5 cars that have ever been built were built to NHRA mandated rules for safety at speeds exceeding 200 MPH. Those speeds are typically coupled to 1/4 mile ET's that are in the -8 second range. In order to be able to travel at speeds above 200 MPH and do it in less that 8 seconds requires power. Power in the 2000+ HP range is typically what it takes.
And the frames and cages in those cars are all built using 1-5/8 .090 wall chromoly tubing.
Now.
I'll write this real slow so you wont miss anything.
If These guys can make that much power, and go that freakin' fast, and the NHRA only requires a weenie little 1 and 5/8 inch, oh ninety wall tube, to be considered safe............
What the hell do you need a 3" round tube for again?.......... I forgot?