I liked that episode. You can get that cylinder head mod done from Indy. INDY also claims some disputed numbers from there CNC port work.

What is done is the pushrod tube is filled in. Steve did it with aluminum shavings and epoxy. Lay the head on a flat surface, mix epoxy, pour & fill into the pushrod hole, let it sit and become soild. Port when hardened & ready. If can also be done with an aluminum rod with an interference fit. I have read some guy did it in this way. He also used a, forgive the lack of a proper name or term, lock tight to help keep the aluminum in place. At this point the port can now be ported wider.

Since the pushrod has to be moved over to activate the rocker arm, the rocker arm itself has to be made offset. So, yes, angles change. But this has been done by most every manufacturer of engines. Here the offset rocker arms or custom offset units are strong enough for most any application. Of course material of the arm maybe the limit as some are better than others under a heavy spring load.

Pushrod angles in the small block are far from perfect. You will loose some lift with the stock angles. If the geometry is off at the rocker, you loose more lift. The MP 48* race block fixes this issue with straightening out the pushrods. But there is still an angle on a left to right as looking at it from the side of the engine.

All of this negitive pushrod angle is still worth the opening of the port. Of course, how far the head can go is the limitation. But the limitation level has been removed for a higher level of possible air flow. And that of course is (potential) power!

The amount of offset has to be carefully calculated for not only clearance but to get the pushrod as straight as possible in the right position. Which more than likely will require adjusting the height of the fulcrum point of the rocker arm for good rocker tip to valve stem workings.

Once all of this is sorted out, even on a stock iron head, X. J, 308, etc... or the factory hp head like the ‘70-340 TA/AAR 6 pack head, it should be a kick ass head for what ever head you start with vs what you end up with. As mentioned earlier, the development of the W2 & W5 Head do not even have a pushrod hole to deal with and require the offset rocker to even operate the head. (Expensive! But worth it IMO when racing.)

I feel the work shown on Engine Masters is a bit adventurous for most guys at home, IF I felt confident on my head porting skills to start with, I’d give it a whirl. It is not a lot of work on top of porting the head. It just the whole job is a lot.

Refer to a pro head porter for more information and possible worth and cost for this mod. If such a mod is worth the cost and added performance over a ported stock casting of what ever head your looking at. A well ported Edelbrock Head does very well. So it may not pay at your level. That’s for you to figure out and I’d do it with a long talk with a pro head porter.
At least “Other Options” can be discussed that may be better. Check your dollars and sense!