Depends...I got 9 season out of one only thing I did was clutch plates once and plugs twice a season.
It hit the wall a few to many times and the cases were twisted but it made it 80+ laps before it went poof.
One of the resons i want EFI is you just toss it in and go. I don't realy ever mess with my motors but i doo search for spec on parts, like cam gears that are factory can and do have 10 deg of tolerance so i look for ones that are as close to factory spec as possible. I never got to do my 600 car, my back was blown out and i was traveling all over the world for work.
Sky's the limit on prices but Dwarfs ARE with out any doubt in the mind the cheapest form of racing.
you can find races ready cars in ther $2500 to 3500 range all day. My cost this year for tires was $425 for the ten races and theres still meat left. Gas is mixed 50/50 110oct ($85 / 5gal) and preium pump gas, maybe 3 gallons a weekend