[crazycasey]

So, I'm going to certainly offend some people here. I've got an engineer buddy who's fond of pointing out people's proclivities towards applying "Brand X" technology towards more unique power plants; in our discussions it has generally centered around Chrysler Hemi engines, but in this case, it's the Ford Flathead.

The staunchest advocates (on this thread) of the 96" tappet bottom radius as being "absolutely necessary" (you know who you are) have all said that it is because the camshaft lobe is ground with a slight taper, and without the corresponding camshaft follower (tappet) radius, the camshaft will ultimately go flat.

Well, I walked into Dema Elgin's office yesterday morning; if you don't know the Elgin name, one need only glance around Dema'a office at the multitude of signed "Thank You" photographs from all the record setting Bonneville cars he's ground camshafts for, to see that this man knows his business (Vern Tardel's 177mph Blown Flathead Roadster is among those cars). I had told Dema that I had a set of NOS Ford Tappets that were flat, and that I wanted them resurfaced with a radius on the bottom. AND, I had told him that Ron Iskenderian had specified that I run a 60"-80" radius for best results.

Well, as I handed Mr. Elgin the box of tappets, he was astounded, first, that they were in fact NOS, but not surprised in the slightest that they were totally flat, but then he went on to explain WHY flathead tappets are flat. He dug around for an old technical drawing of a flathead camshaft, and explained that flathead cams DO NOT, in fact have a tapered lobe. The 96" radius was purely spec'd on an engineering sheet to make up for any inconsistencies in tappet bore to lobe alignment, but the tappets are in actuality, flat.

Well, what about Ron Iskenderian's recommended tappet radius, stories of Isky articles recommending against running stock Ford tappets on reground cams because they're flat, etc. Dema told me to call Ron Iskenderian, and to ask him if his flathead camshafts had any lobe taper. And he said to be sure I tell him Dema Elgin's the one asking. And Ron said, you know, I'm not sure, I know the OHV V8's do, and that's where you need the 60"-80" radius, but I'm going to have to go to the blueprints and get back to you about the flathead. Mr. Elgin was shaking his head.

The next day I get a call back from Ron. Flathead camshafts, including Isky grinds DO NOT have a tapered lobe. And you can run a flat bottomed Ford tappet all day long, but having a tapered radius is still good insurance against tappet bore to lobe alignment inconsistencies, and so he'd still recommend it.

So, there you have it, straight from the mouths of two living legends, two of the most successful names in the camshaft business...you guys are all wet! Though, ultimately your advice is still sound, and I'm greatful to have gone on this journey to know definitively (what I keep asking) WHY!? And to pass that info on to anybody who's still paying attention...