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Vincent Sabatini Vincent Sabatini, RHR Communications

The Head Dept. is a very complex area at RHR and holds several highly proprietary speed secrets. After much thought, we decided to present this in generalization.

I met with Mike, ‘the big Norseman’ who actually runs several RHR departments including the Head Dept. early at about 5:30 am. He was wandering around the machine shop floor ‘French curling a 454 crank’. Yeah, holy crap- that’s when this guy starts work.

Let’s try to break this down in layman terms what goes on here.

Once the heads are back in the machine shop the bare castings are hot tanked and checked for cracks. Here again, an experienced eye can pay dividends.  The heads among other items are again cleaned by ‘abrasive blasting shot peen, soda, glass, etc’. They’re examined once again. No one wants to perform days of work on a casting that’s junk. (“I’ve even seen the best manufacturers ship parts that get damaged or have flaws.” Glenn Hutchison)

When chamber volumes are measured, you’d better be good at math!

Vacuum testing, seven angle valves and seats, combustion chambers are measured along with rocker ratios all in an effort to determine what the final compression ratio will be. Imagine just with this data and Mike can project the final compression ratio.

Cutting seats with accuracy and extreme precision.

More attention is given to the valve guides, facing the seats and clearances. Mike gave me an example of his experience when he was working on some guides. Mike said to watch the valve. I did and the valve slid very smoothly out of the guide. He said, “That’s one-thousandth clearance.” We checked and just by his experience it was, 1 thousandth in clearance.  He even allowed for the temperature to expand it on the day.

Dam this guy is as good as they say ! (No wonder he’s married to a model)

The Norseman said, “Surfacing is done last, just before assembly.”

The seats are marked and ready to be cut.
Mike lapping valves for the perfect seal.

Again, this is a very basic overview. More details like what kind of cam, roller, hydraulic, flat tappet, cam lift, rocker ratio, etc… are calculated to work perfectly together for maximum results- horsepower.

You see, you can bolt on, grind on and so-on until your blue in the face. It’s what, when and where you do this extremely precision work that’s important.  Experience tells these master machinists and builders what they need to do. There is no substitute for experience here.

After watching Mike, no two engines are the same- this job is about a vast breadth of detailed an intricate knowledge, countless years of racing engine building and machining experience.

Mike vacuum checks each combustion chamber individually to verify the seal is perfect on all seats and valves.

“Experience building all forms of racing engines gives RHR a heads up on other builders who just specialize” Rex Hutchison 2012.


Ad copious amounts of diligence, a highly skilled machinist and you get heads that flow like a big dog and we all know big dogs hunt baby.

We’ll have more from the big Norseman about balancing, welding, the art of porting, crack repair and  ‘Civil War Re-enactments’…  WTF did he say  ……  so stay tuned for more.