The price of a pair of X or J heads. That's a good question. The prices are all over the place for a good set. However, if you want to sell them, price them in $300-600 range. The problem is lining up the right customer. If someone is restoring a vehicle and wants date code correct X or J heads, for example, they will pay more than the average performance nut trying to upgrade a SB mopar on a budget. Most people that ask a $1000 for a rebuilt set of X or J heads will have a much harder time selling them. Refer to numerous high buck rebuilt X and J heads that never move on EBAY. Bottom line: There are a lot of new cost-effective and better flowing head options available today in steel or aluminum once you reach the $1000 price range. I think the heads you describe in this post offer a potential performance nut on a budget a few good features. They have the 2.02 valve, new seats, banana cut rocker shafts with the adjustable rockers. At $400-450, the heads are a good value if the customer just has to replace seals and springs. Most people that would buy these heads will replace the seals and springs. You can buy seals and springs for under $300. For a $700 investment, you will have a nice set of heads that will enable you to get an A body running in the high 12s or 13s.
