[olddog]

I suspect most people think cast iron, when they hear cast. I do believe Scat cranks are cast steel, which is quite a bit stronger than cast iron and less brittle.

That said they are a step up from cast iron and the OEMs made some pretty big power with cast iron cranks.

Sure forged is better yet, but it does nothing for you to have more strength than you need.

As for stroking an engine and not changing the cam, heads, bore, or compression, at least theoretically (well there were university studies on flat head engines, so it is pretty true), the engine will have the exact same Hp, but at less rpm and more torque. To make the math simple let's use a 3" stroke verses a 4" stroke.

Here is the rpm, torque, and Hp chart for a 3" stroke.
RPM Torque Hp
2000 - 100 - 38
3000 - 150 - 86
4000 - 150 - 114
5000 - 125 - 119
6000 - 100 - 114

Here is the rpm, torque, and Hp chart for a 4"stroke in the otherwise same engine.
RPM Torque Hp
1500 - 133 - 38
2250 - 200 - 86
3000 - 200 - 114
3750 - 167 - 119
4500 - 133 - 114

The reason or theory is that the maximum air flow into the engine is limited by heads, valves and the rest of the induction side, as well as the exhaust side. So at any given CFM the Hp will be exactly the same. With a longer stroke that given CFM will occur at a RPM that corresponds to the ratio of the stroke change. Thus the torque will increase by the inverse ratio of the stroke change.

I pulled those numbers out of my ass, but chose them to make the math easy to follow.

3/4 of 2000 rpm is 1500 rpm - the same cfm of air is flowing thus the Hp is constant.
4/3 or 100 ft-lb of torque is 133.
38 Hp = 2000 * 100 / 5252
and
38 Hp = 1500 * 133 / 5252

So the engine will make more torque at lower rpm. However if you improve the air flow into the engine you can have your cake and eat it too. You will have more torque, more cfm, and thus more Hp.