Originally Posted by chevy454
Battery switch is needed if the battery is relocated, regardless of et/mph. But, your argument is still valid...it's not really the ET that's gonna get ya, it's the MPH (especially in the 1/8 mile?!)...for example, our '69 only runs high 11s on skinny tires, at 118mph...but, our '70 Chevelle runs high 10s, but only at mid-low 120s and requires a bar.
Taken directly from the NHRA online site, IHRA is the same:
When do I need a roll bar or roll cage, and what should it look like?
A roll bar is required in any convertible running 13.49 seconds or quicker in the quarter mile, and in other cars beginning at 11.49. The roll bar is accepted in vehicles running as quick as 10.00 second e.t., provided the stock firewall and floorboard is intact, other than for installation of wheel tubs. The rollbar must be constructed of minimum 1 ¾ inch o.d. x .118 inch wall mild steel tubing, or 1 ¾ x .083 chrome moly tubing, and must conform to the following diagram:
If the floor and/or firewall has been modified, then a full roll cage is required beginning at a 10.99 e.t. A full roll cage is required in any vehicle running 9.99 seconds or quicker, and any vehicle running 135 mph or faster (regardless of e.t.). The roll cage must be constructed of minimum 1 5/8 o.d.x .118 mild steel tubing, or 1 5/8 x .083 chrome moly tubing, and must conform to the following diagram:
The roll cage of any vehicle running 9.99 or quicker, or 135 mph or faster, must also be certified by NHRA every 3 years, and have a serialized sticker affixed prior to participation.
And list of crap you need for a 10 second car is significant: