Muscle Motors recommended it. They said CNC SR will make the power I want at a lower RPM.

I bought the first set of Indy 426SR heads that Indy CNCd. I wasn't to impressed and sent them to Modern Cylinder Head to have them ported. I requested they flow them before and after. On a 4.32 bore they flowed 361.2@.800. Jeff never did port them, he finally did a bowl blend and valve job. They then flowed 386.2@.800. The heads were 210 CC's on the intake port as delivered from Indy and measured 213cc's after Jeff sent them back to me.
I bought a set of Indy Hi-Po heads, they feature a 2.4" intake valve and the I take port measures 266cc's. I had them flowed locally and the intake went 443 corrected@.700. (his bench couldn't do them at .800).
IMO the Hi-Po heads will make at least 100 more hp than my 426 SR's but for my current package they aren't a very good fit. They have poor port velocity down low and my torque numbers suffer drastically. They want lots of rpm to work and the hp peak was north of 7000.