[jim_howard_pdx]

Tight pistons, lose pistons, what is the difference friction wise????

Nothing, because lose or tight, the piston should never have metal to metal contact with the cylinder wall. The only friction is the ringset's drag along the cylinder wall. Even then they primarily just scrape away the oil, and provide spring tension against the oil film.

However, if the piston rocks in the bore, then you get physical contact of the skirt to the bore and that IS FRICTION.

So the key to getting good cylinder sealing, is keeping the piston tight to the bore, so that you can use a racing ring set with minimum friction, but maximum cylinder sealing.

Hope this makes more sense.

I am a big proponent of zero gap rings. Zero gap rings are a risky business with NOS unless you run a water injector to eliminate detonation and to reduce the combustion temperatures.

Our 500+ HP Honda and Wankel engines all run NOS, TURBO's, and zero gap ring sets. They run really well into the 9's and 10's without problems.

Now for any Cleveland 4V engine, if it detonates, you know the quench is too lose. You really need to keep the combustion space TIGHT. Use a 12/1 pop up and smooth it out completely to 11/1. No more than 0.08 clearance at top dead center except you want a kernal space of about 0.12 at the plug. You want 10 degrees at idle, and no more than a total of 32 degrees at full advance. If you run a vacumn advance, limit total advance to 40 without load, 32 under load.

You should be good on 92 pump gas, just run a water injector if you want to keep things a little cooler under pressure.