Sorry it took so long to get back to you. You have a couple of choices Weiand makes one that is good from idle to 6800rpm and Edelbrock makes one good from 1500-6500rpm. Weiand is probably your best choice Edelbrock has been trying to copy Weiands for about 15 years and doesn't quite meet the performance. There are some different ones but they are alot more expensive. Weiand $199 and Edelbrock $210 in US dollars plus shipping to you