My C/Gas Lakester (present record holder at 276.786mph with a fastest one way time of over 282mph) is built based loosely on a Mark Williams chassis plan.....The wheelbase is 218".... ALL tubing is as per SCTA/BNI rules for thickness and diameters with the exception of the cage and driver area - which is 1 3/4" rather than the minimum allowable 1 5/8"...... there are A LOT more diagonals in the "trusses" of the frame than a drag chassis would have (and I have built a few drag chassis').....
The deal is though, that, if you find a low priced dragster, you could have a lot of good, usable parts for an LSR project.... but choose wisely......