596 head performance mods

Top fuelers are undersquare, more stroke than bore and they can rev.

I see where you're coming from Rob and what you say was true years ago before we had the heads and metallurgy that we have now and this is why:

Oversquare engines (larger bore than stroke)

Advantages:

1. More room for larger valves and less valve shrouding. This isn't the problem that it used to be as good, high flowing heads can be had for relatively low prices.
2. Lower piston speeds allow higher revs without stressing the rods. This has become less of a problem as high quality H beam rods have become readily availible.
3. A longer rod can be run reducing side loading, this has also been resolved with readily availible stroker pistons with a higher pin placement. This can cause problems though when the pin gets up into ring lands to compensate for really big strokes.
4. Less friction due to lower skirt loads and reduced piston speeds.
5. Less rotatating mass to get moving.

Disadvantages:

1. Larger bores for a given displacement can add to the tendency for an engine to detonate. The larger piston top area means that the flame front has to travel further to ignite the same volume of compressed air and fuel.
2. Larger bores have a greater tendency to distort under high pressure causing a loss of combustion pressure.
3. Less crank throw means less torque. The piston and rod have less leverage to turn the crank.

All of the above can be reversed in the case of strokers. I hope this sheds some light on the subject and many of the disadvantages of either can be compensated for in a myriad of ways. I may well have missed a few points and I'm sure we can find someone here who can add to this.