Just for informational purposes I have one of the first sets of the TSP LS6 heads that were ever produced without the reinforced welds or new ports. I probably have less than the number 10 head ever produced....No problems YET. (10,000 miles) (not worried because if I do I know TSP will step up to the plate). The car also made great power (450 rwhp with Fast 90 and small 228/228 cam)....