Before doing this, make sure you have downloaded the Official 1.0.1.1 Beta Patch.

1. create new folders: NASCAR Racing 2003 Season/series/pta/ und NASCAR Racing 2003 Season/series/pta/cars/

2. copy series.def, cup.dat, 2003season.ini, all.ini from series/cup/ to series/pta/

3. edit series/pta/series.def

[Series]
car_classes=16 ; Bitwise-or of allowed classes.
given_name=Trans Am ; Unlocalized series name
type=3 ; (0=cup, 1=gns, 2=truck 3=transam)

4. rename series/pta/cup.dat to pta.dat

5. unpack series/pta/pta.dat with winmip (www.horbra.de/winmip/Winmip2.htm)

6. copy the following files from series/pta/unpack/ to series/pta/

make_a.3do
make_a.cam
make_a_light_cockpit.3do
make_a_pieces.3do
make_a_shadow.3do
make_a_ui.3do

7. rename these files in series/pta/ to:

make_a_pta.3do
make_a_pta.cam
make_a_pta_light_cockpit.3do
make_a_pta_pieces.3do
make_a_pta_shadow.3do
make_a_pta_ui.3do

8. choose a carfile from series/cup/cars/ and copy it to series/pta/cars/

9. rename this carfile from xxx.cup.car to xxx.pta.car

10. edit xxx.pta.car with winmip. find 'car_class=1', change to 'car_class=4'

11. (optional) use old setups with new physics: rename setup-file from xxx.cup.sim to xxx.pta.sim