Thread: pro topline casting numbers

Tweet

Originally Posted by bendougcarl

serious race head??... my plan was to take them to a shop to be hot tanked, and gone over and to see exactly what I have.. then put them on my 84 k20 pick up... has a 383 stock heads flat tops, with comp cams xtreme energy, lift .520/.523 duration 274/286, headers, holley 670 avenger...my question would be, could I put these on this motor, and see an improvement? and still use 89 octane? is there such thing as too much head?? haha

Yes, there is such a thing as too much head and you have found it. Those heads with flat-top pistons will make 12.0:1 in a 355 and 13.0:1 in a 383. The large 220cc intake runners will want more revs in a 383 to move enough air to create sufficient velocity to pack the cylinders properly, figure 7000/7500. Those revs will require a more expensive valvetrain, more rear gear and a looser converter, as well as more cam than what you presently have.

In the name of common sense, sell these turds and buy some heads with 75/76cc chambers and 200cc intake runners that will operate on the street with pump gas. 75/76cc chambers with the pistons you have now will make 9.6:1/9.7:1 static compression ratio, compatible with pump gas and your present cam.