Nitro Slot Car

I'm Terrible at fractions,  1/24   1/32  2/3rd? SIze?    do you mean the small little indoor slot cars or are you looking a the Larger Gas powered cars like theses:
https://www.coxengineforum.com/t7921-cox-car-engines#100095

If I remember correctly, Cox at one point did manufacture a "outdoor"  slot track for the 049 powered cars to race on  ( one on Ebay went for Big bucks)  I'm SURE you could install an engine on the frame you made. There is a National Association that makes  Pulling Tractors with 049 power plants!  Check this out:
http://www.ebay.com/itm/70s-1-16-NMMTPA-049-Cox-Competition-Power-PULLING-Tractor-ENGINE-AMD-FRAME-1/261981978367?_trksid=p2055119.c100022.m2048&_trkparms=ao%3D1%26asc%3D20140122153519%26meid%3D859d8e2f9f284bbca7fc800ad1860a2f%26pid%3D100022%26

On a quick google search, 1/24th seems a bit small, but it is BIGGER the the other sizes shown:
http://www.google.com/imgres?imgurl=http://www.hobbysurplus.com/images/store/crr/scalesizes_M.jpg&imgrefurl=http://www.hobbysurplus.com/slotracing.asp&h=310&w=350&tbnid=yiGhuHmBVh5FBM:&docid=rBfrCwDPa30trM&ei=LXPBVYPDGYn_yQT8iZ2YCw&tbm=isch&ved=0CAwQMygJMAk4ZGoVChMIw43f_fCQxwIViX-SCh38RAez