I had the 572-13's on a 572" alum 91 pump gas street friendly motor, and I believe it had JESEL 1.7's with a soft kitty-kat baby cam; everything worked together as a unit for the best outcome; built by Best Machine and making about 760HP/7-something TQ IIRC. Checked lash once and never had to touch it again while I owned it. Put over 3k street miles on it and about 15-20 passes.

It's about finding what you can do with the architecture you're given. There's no X+Y=Z in this. A particular ratio and lobe design will run really good in one engine, and in the other completely unravel. I experienced this first-hand with my dry-sump alum 412" Yates headed Windsor from years ago. It was a nightmare until I spent some time in conversations with Billy Glidden who helped me get things changed around and finally resolved. After that I had no further issues at 9200 RPM....and.....it was ridin'..........with minimal maintenance.

So while discussing what might be best, high ratio/low lift or low ratio/high lift, on first-hand ratios are just numbers by themselves. What might be considered low is high for someone else's experiences, design and operating conditions and vise versa. With that said, to simply grab some numbers toward the extreme of one end or the other is possibly going to lead to disaster, or potentially no improvement vs some kind of noticeable performance gain. Sometimes gains do not overcome the control issues they create. I would suffice to say most high end engine builders tend to walk the middle ground of lobe lift that retains a decent base circle and a ratio that provides the max lift the engine needs based on valve diameter, rpm etc. Controlling valve events and enhancing area under the curve while maintaining valve train stability are big factors in maximizing engine performance.

In the end, race engines are all about compromise, top to bottom. The real job is to manipulate the compromise to the limit and turn it into success. But like Alan (LA360) said, contact Mike Jones.

Wes