Headers or manifolds for 86k10 350 w/ Vortec heads?

jh86 said:

The 8525hkr? Read on a forum they have interference, but other says they work. Do you know?

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Found this in the Summit reviews

I have the hooker manifolds on my 86 K1500, all the bracketry for A/C works perfectly. I did find the need to use 12 point bolts for socket clearance.

I used the manifolds in the photos below on my 82 C10 with GM Vortec heads. They are sold as Dorman and other brand names.

I had to raise the tops of the exhaust ports a little to match the raised ports on Vortec heads. You may also need to do this on other manifolds and headers, as well as choosing your gaskets well. You can see in the second photo below how some exhaust gaskets obstruct the top 1/8"-3/16" of the Vortec exhaust port. That's the last thing you want to do, because exhaust gases are the most intense at the top of the port.

The last photo shows the gaskets I used. I can't remember what they are for, maybe Fel Pro gaskets for 97-up 5.7 liter 1500 trucks. Oval shaped gaskets might work, too, like Hedman #27520. Fortunately, the heads have a wide gasket surface around the ports.