Exhaust gasket 340

[cudamadd]

Hi would like to purchase 340 exhaust manifold gaskets . Question one will 318 gasket fit are they correct ? I read some were that the ports are different ? Not sure it is a 1970 engine . What would be the best ones to get ? .I know they had a heat shield . But way to pricey .Thank you for taking the time to read this 

[Dakota]

Based on advice I received here, I did not use gaskets with the stock exhaust manifolds on my 340.   I used Permatex Ultra Copper RTV instead and it has worked fine.

[cudamadd]

  thank you