Quench: parallel or tapered squish area?

My current Indy EZ heads were a flat surface outside the chamber area, which made the flat quench pad on the piston have a parallel surface in relation to the head surface. My engine builder is recommending what he referred to as having the heads/chamber "softened" to enhance the combustion chamber and to further reduce the incidence of detonation when running north of 10 to 1 compression on California pump swill.

I haven't read much about that concept. Does anyone out here know of this concept?

https://www.speed-talk.com/forum/vi...amp;sid=5e08873a33ce7cfa44f31872daf49ab2

It appears that not many, if any have verified this concept. There's a difference between softening the chamber and tapered quench. Both done for different applications. Pretty high end stuff. That being said if you want to learn from one of the best. De-atomization of air fuel mixture in intake tract of IC racing engines. Here's part 1 there are 3.
https://www.youtube.com/watch?v=f8XG9T8v-ng
Doug

10.0 to 1 compression ratio with aluminum heads on a BB or SB Mopar V8 I wouldn't be the least bit concern with Detonation or Pre-Ignition as long as you run a cooler spark plug and not more than 36 degrees total timing
What elevation are you at and what octane gas are you planning on running in the motor?

The quench surfaces need not be flat, parallel, or horizontal.
Most common use of matching tapers: aims the extruded charge mass toward the spark plug.
My 2-stroke H2 Kawasaki had 2 tapers (2 degrees different) opening as they move towards the bore center.
Actual hemi (geometric shape) may have domes contoured to match the chamber radius - the quench distance (plus some safety for rock-over @ TDC).

I appreciate the input from you kind Mopartarians. Thank you.

Cab, I'm pretty much at sea level and I'm thinking of running California pump premium @ 91 octane and spraying 100 % methanol using a tuned Alkycontrol set-up metered by the Holley HP computer with the water injection add-on. I thought about going to E-85, but it is still not widely available as you get away from major urban areas. I like road trips.

https://www.alkycontrol.com/

By spraying Methanol, I'm thinking I can get away with 11 to 1 or a touch more with aluminum heads. The Holley HP will allow the use of knock sensors, but I still have a learning curve on adapting them to an RB. I never use heavy throttle below 3000 rpm, and that straight methanol makes a significant drop in air intake temperatures and bumps the octane pretty good too.

Is anyone running a similar set-up out there in this low octane world?

David Vizard has a Youtube video of him porting an old school small block chevy closed chambered iron head. He sloped the closed chamber part toward the intake valve on the intake side of the chamber. Left the exhaust side flat and claimed there was no benefit to sloping that area.