I'll called John today at 4:45 PM, and he answered immediately. 

I emailed last friday and got a response saturday.

I always check the CCs of the combustion chamber for a serious build.   I haven't done anything with these yet, still in plastic bags.  I will try to get one out and flow the ports and cc one of the chambers.  Joe-JDC

JDC

Joe,  Do you double check the combustion chamber volumes?  They're advertised as 60cc but Ted says they can vary and can come in lower (around 56cc).   I'm curious what you are seeing.   Bill

Just received a pair of the Mummert aluminum heads from them.  Joe-JDC

JDC

I spoke to him a couple of weeks ago.  I had left a voicemail about a parts purchase and he called back the next day.  He sent me an invoice by email.   I had a technical question and he answered by email.  My parts arrive this week via UPS.

I've left voicemail for John Mummert and even sent a First-Class letter, hoping to get a price on his SRP forged flat-top pistons, but he hasn't replied.