Shelby exhaust cross-over under intake?

[SeanSide]

Hi! I'm wondering what shelby did about the exhaust cross-over under the intake?
- Did he block the cross over ports inside the heads by filling and smoothing the exhaust ports?
- Blocked with plates on the intake gaskets?
- Did he leave them open like stock?
- And why?

Other forums on the internet seem 50/50 split on the exhaust cross-over dilemma. Some say an engine NEEDS heat to atomize the air/fuel mixture. But i feel that is non-sense. I have never seen an ATV, motorcycle or any recreational motorsport vehicule using some kind of heated intake beside some rare models of snowmobiles having coolant heated carburetors (for obvious snow and temperature reasons)

I watched an episode of engine masters where they found out lowering fuel temperature in the carb bowls increases output. i imagine keeping the intake cooler by blocking the cross-over  would limit that effect and reduce the chance of fuel boiling if you get caught in a stop and go situation during summer.

What are your thoughts and experiences?
Thank you!

[gt350hr]

    SAI didn't modify heads or intakes to block off the heat riser , "in the day".  I do know that they did on occasion use a thin piece of steel to block the port "at the gasket". Aftermarket gaskets were also produced without the opening which did the same thing. Yes , reducing heat in the manifold always makes more power. The passages were for better operation in colder climates , and is common on "most" carburetted engines . The advent of electronic fuel injection has eliminated the need for it now.

[SeanSide]

Thanks again for the information Randy!

[shelbydoug]

I just bought a Mr.Gasket SB engine set and they still include the stamped steel crossover plug that you slip into the gasket.