Originally Posted by Diputado
I've been researching aluminum heads for my 289 over the past several weeks, and have noticed that some (TFS, Edelbrock) recommend drilling "steam holes" in the block deck surface to match those that come on the heads, in order to avoid overheating problems, they claim. Others (AFR,etc.) apparently don't have these holes or recommend them. What's the deal here? Are there significant advantages to these steam holes? If so, why didn't Ford catch on way back and make them standard? Or, are they just unnecessary additional complications? Opinions...experiences?
ok found it. if trick flow does say to do it so do it i guess. since real heads like eddy's and afr's say not to then don't do it when using their heads. the eddy and afr heads apparently do not cause this problem that the trick flows do.
Trick Flow Twisted Wedge heads need pre 72 block water holes added.
"Note that the large coolant holes always go toward the rear of the block. If you have a pre-1972 block or a 351 SVO block, you must modify the coolant passages in the deck surface as shown in . Using the head gasket as a template, drill into the water jacket at the locations shown with a 3/16 in. drill bit. This modification must be done to prevent overheating due to steam pockets forming in the high side of the block. Be sure to tape off or otherwise cover the deck surface and cylinder bores when you are drilling."