Innovation, not money drove his cars. Finding "cheaper" ways to go fast was the way to do it. You don't see that now, because to keep up you need the expensive parts.
A good friend of mine's uncle was friends with Grumpy and they were at the NHRA event this year that honored him. Friend said that everyone was drooling over the "fake" Grumpy cars and that ESPN walked right past his real car without a second glance. Part of me is mad about that, but the other part says "Damn, he really did do it right". No one expected anything out of his car(s), but they ran with the best of them!