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Picked up this extrude honed GM base manifold with my recent Superram purchase. Already have a base,so here we are. Casting number 10066013. It's been nicely extrude honed. Lots of pics. Head side is gasket matched to a 1256. One picture shows the gasket matching the ports. Another shows the gasket on a stock untouched base and you can see the difference. Runner side is opened up to about 1.7", as opposed to the stock 1.66" to 1.68". The beauty isn't the opening though, as much as the material removed inside the port where it immediately chokes down beyondthe opening diameter, as shown in the side by side pic. The only aftermarket base I've owned and measured was an Edelbrock, and these ports are larger and smoother. I won't make performance claims, but this is clearly I nice part. What is "nice"? I suppose that's in the eye of the beholder. To me, that means about $300 plus shipping.
Quick edit...second pic with the micrometer...if it's not clear, that's the ported base on the left, another stock unported base on the right for comparison.
11-17-2018, 08:22 PM
