[Gearhead forever]

can anyone tell me what the physical exhaust port sizes and spacing is on a SBC Vortec head? I'm looking at used headers and would like to confirm they are for a GM. The primarys look pretty oval to me. I dont have any access to measuring myself at the moment

thanks!

[DoubleVision]

It should be rather easy to tell if they are for a GM. It don't matter any what shape they are, it's effect on flow isn't enough to even worry about, especially in a street application. There's been SBC heads with "D" shaped ports, oval shaped, or the stock shape and unless you plan to spend some money on a set of custom headers to match the shape of the exhaust port standard headers work just fine.

[spinn]

Originally Posted by Gearhead forever

can anyone tell me what the physical exhaust port sizes and spacing is on a SBC Vortec head? I'm looking at used headers and would like to confirm they are for a GM. The primarys look pretty oval to me. I dont have any access to measuring myself at the moment

thanks!

This is from my journal, it is assembled for over a year no problems.

906 vortec heads and 9006 summit $100 headers. Great fit and rockstar performance.

[Gearhead forever]

Thanks guys - the concern I have is that I've read that exhaust gaskets can be an issue with vortec heads and small primary headers due to the reduced area of coverage in the corners of the ports - I've heard some complain that they burn out in the corners in a short timeframe

[DoubleVision]

If header gaskets are a concern, then here's a few tips. If you use paper gaskets soak them in water 24 hours before installation. The water makes them swell and makes them hold moisture so they don't burn out as easy.
However, to make things easier and cheaper, I use stock exhaust manifold gaskets. These are made of meshed steel so they don't burn out easy. Plus they're slotted so all you have to do to install them is loosen the header and drop them in, you don't have to take the bolts all the way out as you do with paper gaskets. Another benefit to exhaust manifold gaskets are if they don't stick to the surface upon removal you can reuse them countless times.
I'm not sure where you heard the possibility of the sealing surface being reduced but I can't say I've ever heard of it. I've did a few builds now with Vortec heads and we haven't had any issues exhaust sealing wise.

[warren57]

Watch the spark plug location. I believe that is the change on Vortec heads. Some header tubes will block access to the plugs.
I installed a set of Hedman Hedders yesterday and the fit perfectly with clearance around everything and good plug access. Their tech dept. will help in making the selection. I was very pleased with the ease of installation.