Yes you do!, there's a huge hole at the bottom of your pocket, go ahead, take a look.
If you don't have money problems now, thats great, drive your car and continue to be happy. But DON'T take out a loan that will charge interest to spend on something that can only depreciate. It just doesn't make any mathematical sense at all.
But hey, I'm just another voice on the internet. Please go to any of your local banks, and talk to the qualified loan officers there. Tell them you'd like to take out a loan to put a bigger engine in a 20+ year old car.