[Jim Hand]

blaktopr
Very little work was done at the push rod bulge. The bulge has been flattened, and the chamber side "rolled" smoothly into the wall. As the heads are on the car with the intake in place, can't measure them, but do have a similar head on the shelf with one port finished. The actual width of the opening at the bulge is 1.075". Typically, I try to open the upper part of the port to the maximum width I dare to (without breaking into the push rod opening), while not worrying as much about the lower third of the port entrance. And I did raise the port entrance and blended it in about one inch. I have finally realized the push rod bulge area is not the restriction for this amount of flow. Rather, the turn area and lower bowl area are the critical points.

Incidentally, the port entrance was raised primarily to assist in minimizing the angle from the intake into the head as the air comes out of the intake runners. And the intake runner outlets were also sized accordingly. I have tried the suggestion in the HO books to narrow the intake runner at it approaches the bulge, such that the runner outlet and port inlet (at the bulge) are roughly the same width. However, in ever case, flow through the intake and port together has dropped significantly! So I open the port opening to the dimensions noted above (2.17 X 1.15), and do the same for the intake. I have the intake "interlocked" with nylon adapters such that it is correctly aligned when the front intake bolts are installed.

But it all works - the car is just as fast as it was with the 273 cfm Al D ports, almost .2 quicker, and almost .1 quicker to 60'. And that is with the added 50# of the iron heads.

Jim Hand