Jerry:

To start, a Dooling 29 is not an ideal rat racing engine. On a bet I did build a rat with a Dooling back around 1960, but I had to use a pen bladder tank to get it to run reliably.

I don't know of any kits available, but if you can find an old Testor's "Freshman 29" it can be cut down to make a pretty good one, or the old Harter's "Royal Rodent" or "Student Prince" were good also.

Picture is my antique (45 year old) Student Prince cut down for rat racing. OS Max I 0.35 engine. The spinner had to be taken off for legal racing, of course.

Bill.