Engine was rebuilt before I bought the car, yet mostly stock 318 with edelbrock 4 barrel, and never dyno'ed it. I am sure someone will have those tail gaskets you need. They keep dust and water out too. Spring Fling is a great show, and I always go to them. Early a parts pop up around the show so keep your eye out for em. Get there early! I found a few deals over the years... I have a bunch of parts so let me know what you need for your valiant and I might have it. Gabe