Several years ago we plugged the heat riser passages of a stock Chevy intake manifold on a race engine by pouring them full of molten aluminum- - - -all the way from the cylinder head hole to the carburetor base, from both sides. After one season of racing, the plug was gone! The thermistors we used in the headers during dyno runs on that engine indicated an exaust port temperature at full throttle under load of 2,000 degrees Farenheit.
Jerry

Edit: Any True Value hardware store, or Lowe's, or Home Depot will have the tap, at a cost of about 5 bucks.
Jerry


Last edited by Hotrod Lincoln; 01/12/2011 5:13 AM.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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