I changed my stock heads to ported big valve heads with a ta-49 with a 3 inch DP and cold air pipe. No tracks times but a good power gain. The stock heads are not the best flowing heads. A great first step to going high tens. I went in the tens with it after a few years of the " Just a little faster, thats all" gig. If you are not going to race it alot or not worried about the all mighty horsepower number, then they will last you the life of your care with little problems.