03-13-2016, 12:57 PM | #11 | |
Senior Member
Join Date: Jul 2000
Location: North Texas
Posts: 3,562
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Re: Restoring Rusty
Quote:
Vortec exhaust ports are raised relative to the header bolt holes compared to conventional heads. The trick is to find headers and gaskets that are "tall" enough. A huge percentage of exhaust flow is at the top of the port so it's imperative not to block the opening. As long as the gasket and header openings are the same size or a little larger than the head ports, you'll be fine. As I recall, 1.5" x 1.5" gaskets will work fine. I used these stock 1997 replacement FelPros on my Vortec heads. And then raised the ports on my cast iron manifolds. An old racing trick where rules limit header primary tube size is to raise the headers on the head. Although this covers up the bottom of the head port, that loss is FAR outweighed by the gains at the top of the port where the denser and higher velocity gasses now have more room to move upwards and outward.
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
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