installing a rollcage in a 72 dart that should run mid 10's. I know I don't need the bars that run out through the firewall to the front frame to meet the
nhra rules but since it is running a manual transmission I wondered how much extra support it may give the frame to keep it from twisting? if It may be worth the extra work to install them anyway?

For a 10.00 and slower car all that is required is a 6-point roll BAR. I like to recommend at least an 8-point, which mounts two bars from the leaf spring mounts (or ladder bar mounts) to the cage to help support the main "lift" point of the chassis.



Generally, the stiffer you can make the chassis, the better the suspension will work and the more efficiently the power can be applied to the ground. A roll CAGE is required for cars 9.99 and faster.




Then for more serious power a full tube chassis is recommended.



So to answer your question, yes it will help the car work better. However if you are shooting for "mid 10's" the full cage is a lot more than is required.

Scott