I've heard that Comp's "Thumpr" series can work fairly well. I have not run one myself in anything. But, the word from respectable people was that it's a fairly good product line.

They tend to be a bit long on duration, and ground on a slightly narrower lobe center than most. This allows the intake to close at a slightly earlier point, which tends to require a little less compression ratio. but, they still have reasonably good breathing potential, due to the extra duration.

Just a possibility to keep in mind